The files in theis directory are the sources for files that are used by the trackers and optional functionality. It includes unminified javascript and source files used to generate javscript and css.
To build Boostrap, install nodejs and then do the following -
$ sudo npm install -g connect@2.1.3 hogan.js@2.0.0 jshint@0.9.1 recess@1.1.9 uglify-js@1.3.4
$ make build
The files are now located in docs/assets