Don't free a font that hasn't been created
Don't clear glyphs if the face was never created.
working on guide for choosing colormaps. Have overview section and start on a few others.
added colormaps guide to beginner guide
some more text to colormaps
BUG : fix  _reshape_2D bug with [(n, 1), ..] input

cbook._reshape_2D the input can be _at most_ 2D, however if it
is passed a list of (n, 1) shaped ndarray this condition will
be violated and it fails to work (which is less than great, but
fine from a documentation stand point).  However, boxplot _used_
to work with a list of such ndarrays (and users might expect to
call a (n, 1) shaped array a 1D array).  The added `ravel` makes
sure that even if we get a list of any dimensional ndarrays in, the
output will be a list of (n, ) shaped arrays.

Closes #3220
Change num lines to int in hatch.

Fixes numpy issues warnings
Index with an integer in test_axes
Number of verts in simplification is an int

Fixes numpy warnings in indexing
Explicite cast to int in colors
Cast steps to integer in cbook
Cast to integer in bezier for indexing
Cast to integer in contour

as suggested by comment
Integer division in mlab test
Integer division in trirefine
Filter warnings in rcparams test.
Suppress some more warnings.

These are genuine too so we filter them
Catch warning thrown in Mollweide projection.

This happens when plotting tries to expand
the interval for ticks beyond the defined region and do np.arcsin(y/sqrt(2))
where y is larger that sqrt(2) since the original limites matches the allowed
interval.

And Improve warnings message to clarify that this is related to ticks only.

Also some PEP8 around the code that I changed.
Filter warnings with more selective np.errstate context
Remove redundant cast to int