Better build automation.

The ./build script is no longer dangerous! It will also give you
instructions. It requires that you have a ghp/ directory in the project root,
which will house your gh-pages branch. As to avoid namespace conflicts, that
folder is ignored by this repo now.
Switch to "readable" Bootstrap theme.
Fixed webchat link.
Fixed some contributing info in the README.
Merge branch 'f/pharpend/btrauto' into develop