DOC:Use monospace for --

The -- is rendering as an en dash on http://matplotlib.org/users/pyplot_tutorial.html

Maybe all strings should use monospace instead of single quotes?
DOC: Change all strings to ``'monospace'`` in quotes
DOC: Change strings to monospace
make all optional backends respect the cfg file
cleaning up OptionalBackendPackage a tiny bit

 - check for `if config is not None` before the try/except/pass adds
   nothing, just makes it less readable
 - much clearer to handle of the default value of the `install` variable
   with the base class and not nested in a try/except of the
   `get_config` method (and even duplicated outside of the try/except)
 - the `force` attribute (only used for BackendAgg right now it seems)
   should also have a more prominent default state in the base class
   rather than in just one subclass
move general check() method of optional backend to base class

also split up the if/else in 3 branches to show a separate message if an
configuration file backend opt-out was overridden by a forced backend
install
replace checking of configuration of optional backends in overridden check() methods by a super() call
refactoring/separating backend checks for config file/dependencies

 - config check is handled handled in optional backend base class and
   calls separate dependency check
 - dependency check is an empty stub in base class and can be overriden
   in subclasses
update list of gui backends in config template
refactoring and unifying OptionalPackage and OptionalBackendPackage
replaced `col2hex` which seems to have gotten lost in a bad merge
pep8 fixes
pep8 fixes
converted import-critical PyQt calls to new style so that it will
not seg-fault when using PySide

Addresses issue #2378
pep8 fixes
BUG: Fix IndexError: too many indices with numpy 1.8
second pass at catching the rest of the old-style signal/slot
connections.
change from mdboom
Refactor uploading to S3
Refactor S3 uploading