add color support for Windows

Hi

This pull request brings colors even when running on Windows :sunglasses: 

It makes use of the [colorama](https://pypi.python.org/pypi/colorama) python module.
The only difference is that you cannot have the underlined style in Windows (but the underlined style remains when on other systems)
I tested on a Ubuntu system that the colors aren't broken on Linux after my changes.

![screenshot1](https://dl-web.dropbox.com/get/Captures%20d'%C3%A9cran/2014-01-24_22h43_41.png?_subject_uid=811889&w=AAA8zER1Q8_XY3JiIAJizh4ixh86nPNkx9STtX5oA0at-w)
![screenshot2](https://dl-web.dropbox.com/get/Captures%20d'%C3%A9cran/2014-01-24_22h44_02.png?_subject_uid=811889&w=AADuWac1rzkAK_LW-H5x5qYjUHrGRTu3MFvIJC_BWBZS_A)
![screenshot3](https://dl-web.dropbox.com/get/Captures%20d'%C3%A9cran/2014-01-24_22h44_25.png?_subject_uid=811889&w=AADj6qhC1b3_44KviW2LKADU8lHmOdSodV7U7jYCsxv4iw)
![screenshot4](https://dl-web.dropbox.com/get/Captures%20d'%C3%A9cran/2014-01-24_22h44_47.png?_subject_uid=811889&w=AABE3t-qVZzG3sIfKHbUM7RFCjmcOnDvOykmnaqFOqDhJQ)