Makefile: hg.pot depends on the scripts generating it

This is convenient when editing this scripts. And translators will get updated
translation files even if nothing else has changed.
i18n: posplit writes a warning for translators before rst directives

rst directives like this one have been translated:
.. note::

To help the translator include a comment before such messages.

An entry containing a rst directive now looks like this:

#. do not translate: .. note::
#: path/to/file:75
msgid = ".. note:: to think about"
msgstr = ...
i18n-de: update po file for showing the effect of changed posplit
i18n: posplit removes the entry "::" from the pot file

We do not gain anything by allowing to translate it.
i18n: leave out entries which contain only a rst directive

This prevents the danger of translating entries like ".. note::"
i18n: leave out entries which contain only rst syntax

This prevents the danger of translating entries like the following ones:

.. container:: verbose

    .. input:: filename1.txt
revset: added baseset class (still empty) to improve revset performance

This class is going to be used to cache the set that is created from this list
in many cases while evaluating a revset.
revset: implemented set caching for revset evaluation

Added set caching to the baseset class. It lazily builds the set whenever it's
needed and keeps a reference which is returned when the set is requested
instead of being built again.
revset: added substraction to baseset class

Added __sub__ method to the baseset class to be able to compare it with other
subsets more efficiently.
revset: added intersection to baseset class

Added the method __and__ to the baseset class to be able to intersect with
other objects in a more efficient way.
hgweb: hack around mimetypes encoding thinko (issue4160)

A correct patch for this has existed in Python's BTS for 3 years
(http://bugs.python.org/issue9291), so waiting for it to be fixed
upstream is probably not a viable strategy. Instead, we add this
horrible hack to workaround the issue in existing copies of Python
2.4-2.7.

--HG--
branch : stable
merge with stable