Fix build errors, update bootstrap, fix CSS compression, fix #92.

- It seems that the git submodule for bootstrap pointed to old boostrap 2.3.* and "@import variables" had an invalid path. 
- Updated to latest boostrap 3.0.3 fixed the import path.
- CSS was not minified, fixed the param for lessc.
- Add build.less which now imports variables from bootstrap and is used for building dist files.
- Fix #92, bootstrap-datepicker.less can now be imported from userland and will not throw errors.
- Updated dist files to latest versions.
- Added compilation of the un-minified version to Makefile.