This extension is now builtin and no longer exist under the old name.
Since the test was just verifying that we can load extensions and uses
other extensions, we can just remove it from the test.

This fixes a regression in commit 0f8a8b27
("default: bring some of the jinja2 improvements by refactoring the 2 recipes").

Example:

foo.cfg:

  [foo]
  url = ...

bar.cfg:

  [buildout]
  extends = foo.cfg

  [foo]
  url =
  inline = blablah

Recipes must not distinguish the existence of an option from an empty
option value. It's a common mistake in recipes because that's natural
to do that in Python. However, buildout has no syntax to remove an
option when overriding a section.

This fixes commit 62f55c69
for Python 3.

- try to not rewrite on update if there's no change
- handle 'mode' the same way as in the jinja2 recipe

The expected usage of zc.buildout.download.Download() is that the caller is
supposed to remove the temporary files (cf [1] [2])

[1]: https://github.com/buildout/buildout/blob/3ed7c06bf7be594dcb3c906c2517ee438f059251/src/zc/buildout/download.txt#L55
[2]: https://github.com/buildout/buildout/blob/3da22a7dacb9a4d1f771e7763e014214c31d935b/src/zc/buildout/download.py#L171-L176

See merge request !5

setuptools 42.0.0 prints a warning:

   WARNING: The easy_install command is deprecated and will be removed in a future version

use a test normalizer to ignore this warning in doctest.

Local variable `template` is used for different things, it is bad. Use different variable name for different thing.

compile function takes a lot of time, thus this change saves time when the same source is used many times in apache frontend SR.

__init__ should only check options. By doing the actual work in install/update,
it is now possible to use a template that is produced by another part.

'mode' was implemented like 'umask' but it has never been used this way,
and the 'umask' option is deprecated:
- remove support for unused 'umask' option
- change 'mode' to actually apply the wanted mode, regardless the current umask
- the default mode changes: if 'mode' is not given, the resulting file is only
  executable (actually 0777 & ~umask) if the content starts with '#!',
  else its mode is: 0666 & ~umask