Dvi is a binary format that includes some ASCII strings such as
TeX names of some fonts. The associated files such as psfonts.map
need to be ASCII too. This patch changes their handling to keep
them as binary strings all the time.

This avoids the ugly workaround

        try:
            result = some_mapping[texname]
        except KeyError:
            result = some_mapping[texname.decode('ascii')]

which is essentially saying that texname is sometimes a string,
sometimes a bytestring. The workaround masks real KeyErrors,
leading to incomprehensible error messages such as in #6516.

So if you follow the troubleshooting instructions and rerun
with --verbose-helpful you get a hint about the usual reason
for #6516.

If the class has an internal error triggering this assertion,
we will get some errors later from mixing strings and bytestrings.

These are now ASCII bytestrings so we should not assume they
are strings.

Don't mix filenames and dvi font names as keys of the same dict.

Use re.findall, and open the file as binary.

Improve a docstring, remove unneeded parens from an assert,
open a file as binary instead of encoding each line read from it,
don't call six.b on variable strings, simplify string handling,
improve the formatting of a matplotlib.verbose.report call.

Combine the word splitting and classification in one regex so we
only have to scan each line once. Add some quotation marks in the
test case to check that we are handling quoted words correctly
(the behavior should always have matched this test case).

I'm so very confused so trying to demystify how this works. @QuLogic

Once all the parameters are substituted into the warning message, it
doesn't make grammatical sense due to some assumptions in the message.

Seems to be an obvious omission

DOC: Fixed x, y, docstring in errorbar

* Add README.txt documenting how to use the script to generate
gitwash docs.

Update Slider docs and type check slidermin and slidermax.

Clean up and move text rotation example

Handle dvi font names as ASCII bytestrings

Support for setting the backend with `-dbackend` was deprecated in 1.5.

Regenerate the gitwash docs.

API: Remove support for -dbackend argv.

Deprecate Axes.axesPatch, Figure.figurePatch.

DOC: Add a code block in 'installing' docs.

Fixes typos in Artist tutorial

DOC: Fix small typos in 'eventplot' docstring

Python 3.4 does not automatically import module `abc` into
`collections`, causing an error when checking for
`collections.abc.MappingView`.  Use `collections.MappingView` to work
round this difference.

At some point Python may deprecate `collections.MappingView` in favor of
`collections.abc.MappingView` but we can fix that when it arises.

MAINT: mappingview check for Python 3.4

Addresses #8177, Readme badges