Move source into src directory
Add sphinx doc files
Add gh-pages target to Makefile
Change sphinx builddir
Remove build from Makefile
Merge branch 'gen-docs' into develop
Include mathjax and numpydoc sphinx plugins
Update docstrings in gp.py
Minor docstring formatting in gp.py
Reorganize kernels package
Ignore sphinx _build folder
Update sphinx configuration
Create docs/source for rst files
Change obj to self in selfparams

This is so sphinx detects the first parameter in decorated functions
as `self`, and therefore does not display it in the method signature.
Minor sphinx configuration tweaks
Standardize references
Kernel documentation
Minor sphinx tweaking
Oops, copy shouldn't be a property
Add citation for periodic kernel