Merge pull request #1560 from NelleV/1552_remove2.5

Remove python2.5 support from texmanager.py
Merge pull request #1559 from ChrisBeaumont/master

Workaround for QT cursor bug in dock areas
Removing clip that is no longer needed
make rc_context show up in pyplot's docs
PEP8-compliance on axes.py (patch 4 / 4)
fix rendering slowdown of big Lines (issue #1256)

About the fix:

Line2D.draw method now *returns immediately*,
if the Line is invisible (get_visible() returns False).

In particular, the `self.recache` and `self._transform_path`
calls are short-circuited.

In addition to the bugfix:

* adds a test case for lines rendering speed (issue #1256)
* adds a README in `matplotlib.tests` to redirect people
  to the testing section of the development guide.
Merge pull request #1564 from NelleV/pep8_axes_4

PEP8-compliance on axes.py (patch 4 / 4)
Merge pull request #1398 from NelleV/pep8_dates

PEP8 fixes on dates.py
Merge pull request #1531 from pierre-haessig/master

fix rendering slowdown with big invisible lines (issue #1256)
PEP8 fixes on the tests of the dates module
FIX Removes code that does work from the axes module

closes #1465
Merge pull request #1569 from NelleV/1465_remove_unworking_code_from_axes

FIX Removes code that does work from the axes module
Merge pull request #1570 from NelleV/test_date

PEP8 fixes on the tests of the dates module
Merge pull request #1536 from jakevdp/anim_avconv

ENH: add AVConv movie writer for animations
fix issue #1572 caused by PR #1081
Added missing Sankey.__init__ method
In Sankey, prevented appended lists of labels
Fixed typos in Sankey
Improved margins in Sankey demo
Revert "Added missing Sankey.__init__ method" (it was simply moved)

This reverts commit 80f30301d23d799a86971b02e3b6b4184ca216f6.