Although very unlikely here, it's good pratice to write code without possible
race conditions. The only remaining one here is when anouther process create
a file (with the same output path) between its deletion and its creation.

They should not be needed when buildout handles its own serialisation.

Based largely on work by Timothée Lacroix <timothee.lacroix@tiolive.com>,
plus:
- reworked loader classes
- reduced unnecessary diffs
- added rawfile and rawfolder types
- documented & tested

umask cannot set a regular file as executable, nor allows setting
suid/sgid/sticky bits.
Using chmod properly, there is no security problem.

Useful when extending another section from same file.

This test case was accidentally reusing a previous template.

Noticed by Timothée Lacroix <timothee.lacroix@tiolive.com>

Patch by Timothée Lacroix <timothee.lacroix@tiolive.com>

Patch by Timothée Lacroix <timothee.lacroix@tiolive.com>

Reported by Timothee Lacroix.

Loads support should not be required: the use-case is writing python values
when generating a buildout.cfg file.

Test the latter, and document how to work around the former.

Also, fix pyc files gitignore globing.

Buildout way couldn't install some (dependency) eggs for an unknown reason
(zope.exception on some python environments, Jinja2 needed by a future
extension...) and "setup.py test" just works, with fewer lines at this.
Also, drop zope.testing dependency altogether:
- zope.testing.doctest is deprecated
- zope.testing.renormalizing is not really needed for this test

Squashed commit of the following:

commit 1b0a4e9b58ffe5d831459cc77637cee1bcee30da
Author: Łukasz Nowak <luke@nexedi.com>
Date:   Wed Oct 12 12:00:53 2011 +0200

    Do not tests buildout issue.

commit 51a6b9a187a0bbaa3522756993c5ff17e2b262e0
Author: Antoine Catton <acatton@tiolive.com>
Date:   Wed Oct 12 11:38:57 2011 +0200

    Update .gitignore with editor backup files.

commit 2235385913170d4546cd92b96d2ed1706e94fad1
Author: Antoine Catton <acatton@tiolive.com>
Date:   Wed Oct 12 11:37:39 2011 +0200

    Update .gitignore with buildout generated files.

commit 35bdbf798e504d9e947ed358dbe2f9a74143e2b8
Author: Antoine Catton <acatton@tiolive.com>
Date:   Wed Oct 12 11:36:44 2011 +0200

    Update changelog

commit 64a2d6d8b85850641172d6a79acd6d75c720d449
Author: Antoine Catton <acatton@tiolive.com>
Date:   Wed Oct 12 11:35:56 2011 +0200

    Reformatting egg's long_description

commit 4e53b6bc7791061a57783a7b55b76f96c56fa1c8
Author: Antoine Catton <acatton@tiolive.com>
Date:   Wed Oct 12 11:30:26 2011 +0200

    Add buildout.cfg in order to easily run tests

commit 7c8e7225d344770502ad5aa84d72d2c9b1dc4e05
Author: Antoine Catton <acatton@tiolive.com>
Date:   Wed Oct 12 11:29:40 2011 +0200

    Add tests

commit e03d69efe845d41a3321568ccbf0c6bc187867f0
Author: Antoine Catton <acatton@tiolive.com>
Date:   Wed Oct 12 11:27:14 2011 +0200

    Move slapos.recipe.template module in its own directory in order to add
    tests and so on.

commit be8900ed0f0cf6105ef30881d7c818cb6cc6a0f2
Author: Antoine Catton <acatton@tiolive.com>
Date:   Tue Oct 11 16:32:47 2011 +0200

    Add support of mode option

commit 943b9b62477f454cb25f5118595690a2a0eebcab
Author: Romain Courteaud <romain@nexedi.com>
Date:   Tue Oct 11 15:12:28 2011 +0200

    Use __getitem__ instead of dict.get

commit 0d1b1c68270139d2602b23db1b0943220f463cc8
Author: Antoine Catton <acatton@tiolive.com>
Date:   Tue Oct 11 15:10:26 2011 +0200

    Removing error message

commit a9d677ba9c67c3b06368b56b212898c79cd155ca
Author: Antoine Catton <acatton@tiolive.com>
Date:   Tue Oct 11 15:06:13 2011 +0200

    Use a part dependent hidden option name

commit 87ab4e4b35c3d4696395e24616a2fba6f084cccc
Author: Antoine Catton <acatton@tiolive.com>
Date:   Tue Oct 11 15:04:42 2011 +0200

    Add python 2.6 compatibility by removing with statements

commit 6ab6954b8fb924c96562d1fad83e226f2060bbd8
Author: Antoine Catton <acatton@tiolive.com>
Date:   Tue Oct 11 15:03:04 2011 +0200

    Remove the useless internal 'input' option

commit 022bd83d68460f5e94ab2381b1a33014ecfec93c
Author: Romain Courteaud <romain@nexedi.com>
Date:   Tue Oct 11 14:57:21 2011 +0200

    Drop collective.recipe.template dependency