Sketched functions to do necessary convergence calculations
Initial commit of Gelman-Rubin convergence criterion
Extensive docs for Gelman-Rubin criterion calculations
A file for examining the properties of the GR criterion

Not a test per se, but can be used to run multiple chains for a simple
model and see how the GR convergence criterion decreases with increased
chain length.
Initial commit of Sphinx docs directory
Doc fixes to convergence.py to render math correctly
Added nose tests for calculations

Also fixed a critical bug in the check_chain_lengths function
Added .swp files to .gitignore
Moved test_convergence to examples directory