Improve Documentation

[ylow]

• Rewrote and simplified up a lot of documentation.
• Added API docs
• Removed extra copy of documentation in pyxet/docs
• Shifted the starter titanic repo to xethub
• Fix pypi docs
• Pull the doc version from the package version

Recommended to checkout and run make html in the docs/ folder to see how it looks.

[ylow]

html.tar.gz