Autoscaling and limits in mplot3d.

    * Fixes improper setting of x,y,z limits not turning off autoscaling
    * Adds units support to z-axis
    * Adds shared axis support for z-axis
    * Closes #783
A bit of cleanup
DOC: github ribbon does not cover up index link

thanks @jenshnielsen for spotting the fact that the previous "solution"
didn't actually work as intended.
fix 2 html color names

There are two garbled up lines resulting in one missing colorname and one colorname assigned to the wrong html color code.
Merge pull request #1527 from megies/patch-1

fix color names for paleturquoise and palevioletred
Merge pull request #1523 from ivanov/gh-ribbon-fixed

DOC: github ribbon does not cover up index link
Fix some compiler warnings
Changed mailinglist archive link.
Add workaround for Travis
Fix building on 32-bit
Add citation page to website
Add citing to the list of additional pages
If the user has "savefig.extension : auto" (deprecated) in their (old) matplotlibrc, it will be copied into "savefig.format", where "auto" is not a supported choice.  This will fix it so it becomes "png" if it's currently set to "auto".  This bug discovered as part of #1530, though it doesn't fix it.
Merge pull request #1537 from mdboom/savefig.extension-fix

Fix savefig.extension == "auto"
Merge branch 'v1.2.x' of github.com:matplotlib/matplotlib into mplot3d/autoscale_fix
Some PEP8 fixes for axes3d.py
Merge pull request #1289 from WeatherGod/mplot3d/autoscale_fix

Autoscaling and limits in mplot3d.
inverting an axis shouldn't affect the autoscaling setting
Renamed all instances of variables named "long" to "lon" to avoid clobbering by 2to3
Remove NO_DEPRECATED flag -- this was accidentally committed.