Squashed commit of the following:

commit 5c74964a312fb743f88a115ffb4d5af44dd3d2d1
Author: Łukasz Nowak <luke@nexedi.com>
Date:   Fri Sep 2 10:22:48 2011 +0200

    No more M2Crypto is required.

commit 71ddc285850bd1c5761b95cff8616c6023f6eadf
Author: Łukasz Nowak <luke@nexedi.com>
Date:   Fri Sep 2 10:22:03 2011 +0200

    Drop M2Crypto dependency.

    Simplify, generate only common name in key.

commit 9e058070bc66fc91a590d90adf379a899b00d124
Author: Łukasz Nowak <luke@nexedi.com>
Date:   Thu Sep 1 18:05:14 2011 +0200

    Cover cases when openssl is not compatible.

    It seems that python executable can be seen as openssl begin not compatible.

commit 69901f159392db65597b97482439bea4d002e9c4
Author: Łukasz Nowak <luke@nexedi.com>
Date:   Thu Sep 1 18:00:27 2011 +0200

    Raise correctly in case of openssl unavailabilty during upload.

    More: raise DirectoryNotFound in more cases.

commit c17c46053385b586e7ccdb4ebf3ecb9ab46d901b
Author: Łukasz Nowak <luke@nexedi.com>
Date:   Thu Sep 1 18:00:08 2011 +0200

    Cover case when no openssl is available during upload.

commit d88d9e2b892000fa64c28b74182777fd03c93556
Author: Łukasz Nowak <luke@nexedi.com>
Date:   Thu Sep 1 17:55:23 2011 +0200

    Covert case when empty shadir entry is in shadir.

commit 6671546db794a5ea8e7025de115a613940e4af14
Author: Łukasz Nowak <luke@nexedi.com>
Date:   Thu Sep 1 17:45:08 2011 +0200

    Add no openssl during content selection test.

    Add another test skeleton.

commit ad6b3b5abbbb2d8267938661946acf1bd4d02b43
Author: Łukasz Nowak <luke@nexedi.com>
Date:   Thu Sep 1 17:32:09 2011 +0200

    Close another temporary file.

commit 34d15b585e52810908323cf846af5a64171f62b2
Author: Łukasz Nowak <luke@nexedi.com>
Date:   Thu Sep 1 17:23:23 2011 +0200

    Expose openssl and avoid dying in case if not exists.

commit 0eb456fc6ccd2d36644c47abc1ef79b7b51187c6
Author: Łukasz Nowak <luke@nexedi.com>
Date:   Thu Sep 1 17:15:54 2011 +0200

    Pep8isation.

commit 7179acf759a1d18bff367025a965d020443f93e2
Author: Łukasz Nowak <luke@nexedi.com>
Date:   Thu Sep 1 17:12:25 2011 +0200

    Drop M2Crypto dependency.

    M2Crypto is unmantained library. It seems safer to use openssl directly to
    sign and verify content.

Previously just empty strings were signed and verified.

Squashed commit of the following:

commit b3e1bf51989599a136f2a42f63688aa3048aae12
Author: Łukasz Nowak <luke@nexedi.com>
Date:   Thu Sep 1 15:59:40 2011 +0200

    Really sign the content.

commit c4a6abd652f7ca19fad66188ec7c782956392b68
Author: Łukasz Nowak <luke@nexedi.com>
Date:   Thu Sep 1 15:59:07 2011 +0200

    Show that hacked content is not trusted.

commit 08340918639598b227dd346d4ab6054428296d60
Author: Łukasz Nowak <luke@nexedi.com>
Date:   Thu Sep 1 15:12:09 2011 +0200

    Positive test of signed content.

commit a00a2a5b788542d324561d4d6418b86c1cb9f86d
Author: Łukasz Nowak <luke@nexedi.com>
Date:   Thu Sep 1 15:00:54 2011 +0200

    Skip if no standalone server is available.

commit f31ef55187c46305b2ae8034ee496cc28af12893
Author: Łukasz Nowak <luke@nexedi.com>
Date:   Thu Sep 1 14:32:39 2011 +0200

    Move offline tests to one place.

    Remove non sense tests.

commit d725dcd24b95f5bbbb340a6fe6ce5ea7f8aed4d5
Author: Łukasz Nowak <luke@nexedi.com>
Date:   Thu Sep 1 14:14:34 2011 +0200

    Start to really sign the content.

    Previously empty strings were signed and verified.

Squashed commit of the following:

commit 390841c31c900117ee1bcd96fdb685abc67640ba
Author: Łukasz Nowak <luke@nexedi.com>
Date:   Wed Aug 31 15:00:25 2011 +0200

    Separated SSL test server.

commit 71293ace2e87ba0a7d58261ac37ce203d1660da5
Author: Łukasz Nowak <luke@nexedi.com>
Date:   Wed Aug 31 14:57:58 2011 +0200

    SSL auth shall not be used for download.

commit 9c9decdf247b13b46b1d00977b06060af668ad24
Author: Łukasz Nowak <luke@nexedi.com>
Date:   Wed Aug 31 14:45:01 2011 +0200

    Skip some tests.

commit 8ef48e73192e44563ba21358ab684419d4fc8b70
Author: Łukasz Nowak <luke@nexedi.com>
Date:   Wed Aug 31 10:26:59 2011 +0200

    PEP8ised.

commit 260e0951d724be3f81df25ef7f9fce5d8922be89
Author: Łukasz Nowak <luke@nexedi.com>
Date:   Wed Aug 31 10:25:35 2011 +0200

    Implement tests.

commit 8900f71910210e14d5af92189bb1ab92fb75c069
Author: Łukasz Nowak <luke@nexedi.com>
Date:   Wed Aug 31 10:22:18 2011 +0200

    Implement ssl based tests.

    Unfortunately no internal SSL server with authentication is available.

commit e1818af334ee572838a04d384f5088fef9b9af7f
Author: Łukasz Nowak <luke@nexedi.com>
Date:   Tue Aug 30 15:56:17 2011 +0200

    Provide authnetication SSL keys.

    Also import some CA certificte which validates them.

commit 8b5ee8652975b252623c19be5416812b22bf916c
Author: Łukasz Nowak <luke@nexedi.com>
Date:   Tue Aug 30 15:39:12 2011 +0200

    Mark tests to be implemented.

commit ebce98a58171d90008bd172036642cb04c00ffa8
Author: Łukasz Nowak <luke@nexedi.com>
Date:   Tue Aug 30 15:37:36 2011 +0200

    Test that auth key and cert are accepted.

    Assertion simplified to checking that they are set.

commit 1dc200d15a09d91366962b0d248191d4289304cc
Author: Łukasz Nowak <luke@nexedi.com>
Date:   Tue Aug 30 15:34:00 2011 +0200

    Share key and certificate between tests.

commit eb870df4ed55c595519843c32103ca5d3b9fe24a
Author: Łukasz Nowak <luke@nexedi.com>
Date:   Tue Aug 30 15:30:22 2011 +0200

    Implement SSL based authentication.

    Accept key and certificate and pass them in case of using https scheme while
    putting content to shacache and shadir.

commit ac219f335e687659a2e28719044d7c8267d1dfce
Author: Łukasz Nowak <luke@nexedi.com>
Date:   Tue Aug 30 14:21:24 2011 +0200

    Expose authentication parameters.

commit 1b960b07504a390cc1ecdfd598f4148753176447
Author: Łukasz Nowak <luke@nexedi.com>
Date:   Tue Aug 30 14:19:45 2011 +0200

    Describe parameters.

commit 2a0186478a5c699ac77fa526f31b5a5a92069f72
Author: Łukasz Nowak <luke@nexedi.com>
Date:   Tue Aug 30 14:17:27 2011 +0200

    Reformat parameter list.

Except list of PEM encoded certificate strings. Do not try to read them from
file nor download from network.

Also fix few naming errors.

Compat: Put key as first argument.

Spec: In case of passing key (and updating shadir) require urlmd5 too.

Key is given by the library user. It has no internal meaning.