changed here: d68662a

When determining which pixels to mask in the resampled image, if _any_
contribution to final value comes from a masked pixel, mask the
result.

Due to Agg special-casing the meaning of the alpha channel,
the interpolation for the mask channel needs to be done separately.
This is probably a template for doing the over/under separately.

print out exact hash on travis

This patch adds two new rcParams allowing to set label alignment. The sole
reason for the existance of these new parameters is to allow user to reset the
style to before 2.0 for testing purposes. More specifically, ytick horizontal
alignement was changed in a non backward compatible way. xtick vertical
alignement was added for API consistency.

closes #7905

This allows the public classic stylesheet to be 'more' backward compatible

FIX label vertical alignment can now be specified

This makes the result a bit more reproducable and comparable.

Travis may or may not have a browser installed, but AppVeyor definitely
does, so this saves a tiny bit of processing power per run.

This breaks saving PNG when using the PGF backend.

Fixes #8121.

FIX: invalid arguments passed to pdftocairo in pgf

Set sticky_edges correctly for negative height bar().

MAINT Backporting of #7995.

Fix imshow masked interpolation

MNT: Cleanup visual_tests and disable browser opening

BUG Ignore invisible axes in computing tight_layout

TST: fail on missing baseline file

DOC moved changelog to the documentation

MAINT moved some maintenance and helper python scripts to tools/

Fix sphinx required version

TST: Inkscape shell mode.

Conflicts:
  .travis.yml
     - kept extra lines from 2.0.x to print a few more diagnostics
  lib/matplotlib/tests/test_backend_pgf.py
    - keep master version of test decorators
   lib/matplotlib/tests/test_image.py
    - kept addational tests from 2.0.x
    - removed a @cleanup
  lib/matplotlib/tests/test_ticker.py
   - conflict from b03b71a
     kept master version
Other:
  lib/matplotlib/tests/test_axes.py
    - remove @cleanup

STY: fix whitespace in the tests

The vast majority of examples do not have the executable bit set, so
just make everything consistent.

Also remove `#!/usr/bin/env python` where appropriate.

[MRG+1] MEP12 ganged example

MNT: Remove executable bit from examples and headers.

DOC shapes and collections is fully SG compatible

…-gallery

Removes OldScalarFormatter 

closes #7956

Use neutral pronoun in docs.