Make Axes.stem take at least one argument.

When it takes only one, the abscissae default to np.arange(len(y))
Add axes.stem call signature test
Update CHANGELOG with axes.stem change
Fix positional argument parsing
Make stem catch explicit Exception classes
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.
Added a test for #1553
Remove redundant ob_refcnt's that cause crashes when built in DEBUG mode.
Mac OS X 10.5 needs an autoreleasepool here to avoid memory leaks. Newer versions of Mac OS X do not, but it doesn't hurt to have one anyway.
new MatplotlibDeprecationWarning class

In light of the fact that Python builtin DeprecationWarnings are ignored
by default as of Python 2.7 (see link below), this class was put in to
allow for the signaling of deprecation, but via UserWarnings which are
not ignored by default.

http://docs.python.org/dev/whatsnew/2.7.html#the-future-for-python-2-x

Prior to this commit:

```
In [1]: %pylab

Welcome to pylab, a matplotlib-based Python environment [backend: agg].
For more information, type 'help(pylab)'.

In [2]: mlab.liaupunov([1,2], np.diff)
Out[2]: 0.0
```

After this commit:
```
In [1]: %pylab

Welcome to pylab, a matplotlib-based Python environment [backend: agg].
For more information, type 'help(pylab)'.

In [2]: mlab.liaupunov([1,2], np.diff)
/home/pi/.local/lib/python2.7/site-packages/matplotlib/mlab.py:1212:
MatplotlibDeprecationWarning: This does not belong in matplotlib and
will be removed
  mDeprecation) # 2009/06/13
Out[2]: 0.0
```
Fix the xlim of polar plots
Make font_manager ignore KeyErrors for bad fonts
Change printed -> pretty-printed

Pretty-printed as in `import pprint`
Merge pull request #1603 from mdboom/polar_range

ylim=0.0 is not well handled in polar plots
Merge pull request #1557 from WeatherGod/invert_autoscale

inverting an axis shouldn't affect the autoscaling setting
Merge pull request #1605 from dmcdougall/fix_whatsnew_typo

Change printed -> pretty-printed
Merge pull request #1604 from dmcdougall/fix_badfonts

Make font_manager ignore KeyErrors for bad fonts
Document the C/C++ code guidelines