added a basic SunPy region-of-interest (ROI) object that can accept times of interest and string descriptors.
typo fix for roi.py
first hack at adding structure for docs
forgot to add these files
Merge pull request #1 from ehsteve/roi

first hack at adding structure for docs
Update roi.rst
editing the roi file comments for consistency.
added a test for roi object in sunpy/tests/roi.
Merge pull request #655 from aringlis/roi

Created a basic region of interest (ROI) object that accepts times of interest and string descriptors