MAINT: Make ad-hoc fixes to avoid errors for doctest nose
DOC: Add doctest module for the documentation
DOC: Add instructions on using doctest
DOC: Add subsection titles to quickstart guide
DOC: Use RST instead of Notebooks for user guide
BUG: Fix Gaussian and GaussianARD initialization
TST: Add unit tests for GaussianARD initializations
DOC: Use RST instead of Notebook for Quick start guide
DOC: Write inference section to user guide
DOC: Sketch Examine results section in docs