Merge pull request #3650 from cbrueffer/misc

DOC : Typo fixes.
Conflicts:
	lib/matplotlib/axis.py

Conflicts due to pep8 work on master branch.
Merge pull request #3640 from emikulic/master

DOC : figure.max_num_figures was renamed to figure.max_open_warning.

This was done in 8c8bc8f71aa373b076d8790e14046c940a5269e0 and 0433bd59e43e63ea792a970c32a883e4aaa3d086
Nose and Mock as tests_require deps, test command

- require nose and mock for tests, not for normal installation
- implement a test command in setup.py for invoking tests
Feature test command in readme