Initial work on sphinx documentation
Switch from markdown to rest, which works better with Sphinx
Updates to get Sphinx to work with the ghpages output directoy
Some work turning doc strings into Sphinx docs.
Better setup of the basic doc hierarchy
(#9)
Some tweaking of doc strings to make them look ok in Sphinx
(#9)
Merge branch 'master' into #9

Conflicts:
	.gitignore
Add link to docs from README
(#9)
Update docs of angular unit conversions
(#9)
Some work on improving doc markup
(#9)
Merge branch 'master' into #9
Move set_omp_threads to config.py
(#9)
Improve docs for config utilities.
(#9)
Updates to CelestialCoord docs
(#9)
Update docs for Catalog, Fields.  Also simplify the syntax of the latter slightly.
(#9)
Update docs for corr2 function
(#9)
Updates to the various Correlation docs
(#9)
Use mathjax for the math in the docs
(#9)
Rename some files with n2->nn, g2->gg, k2->kk
(#9)
Change G2Correlation->GGCorrelation, and similar for N2, K2
(#9)