Added `# FIXME` comments where docstrings are needed

Conflicts:
	pyvows/core.py
`color.py`: Tweaked module-docstring
`color.py`: Added docstring for `NoColor` class
`console.py`: Added docstrings
`console.py`: Edited & moved main description string to `Messages` class
'core.py`: Added docstrings for _most_ module members

A few members of this module contain code that I really don't understand. ☺  I didn’t write docstrings for them.

Hoewver, if any specific questions came to mind, I wrote them in a comment below the `# FIXME: Add docstring` comment.
`reporting.py`: Added missing docstrings
`result.py`: Added missing docstrings
`version.py`: Added missing docstring
`xunit.py`: Added missing docstrings
`assertions/__init__.py`: Updated package docstring
`assertions/*`: Added docstrings for all assertions
Merge pull request #61 from Zearin/feature/#49-add-missing-docstrings

Feature/#49 add missing docstrings