pytest: ignore all .* directories

Don't duplicate error case in package_index

easy_install has code to handle parsing a requirement, catching the
ValueError and then raising a DistUtilsError. This code was entirely
duplicated in package_index, so I've slightly refactored to remove
the duplication.

easy_install: update links to documentation

Allow get_unpatched to be called to get unpatched version of a class or function, further harmonizing the interfaces.

Consolidate function patching and resolution of unpatched function, aligning pattern with the patched classes.

Move msvc import to avoid a circular import

Use EXT_SUFFIX instead of SO for py_limited_api renaming

In Cloud9 a .c9 directory is created. Other IDEs like to add .directories as well

Use LegacyVersion instead of LooseVersion

- Also apply the patch for numpy 1.11.2 pre release

Use LooseVersion instread of StrictVersion

Remove private prefix from monkey as monkey module explicitly declares that all functions are private.