Refactored color module (and dependent code)

Started to move a few color-related methods from the classes in `reporting.py` to `color.py`…then I realized, “If I’m going to do this much, I might as well make the color module be easier to use for all of PyVows.”  

So, I added some convenience methods to the colors module for the main ANSI colors.

After updating the dependent code (mostly in `reporting.py`, teeny bit in `console.py`), the result looks much nicer.  Easier to read, too.

w00+!  :)