Add grunt and needed plugins for minifying

Adresses #219
Add Gruntfile to configure minifying

Adresses #219
Add minified file and sourcemap to bower package

Adresses #219
Add info about installation of dev dependencies to README

Adresses #219
Add minified version and sourcemap to version control

Closes #219
Merge pull request #235 from mischah/feature/minified-version

Add minified version via Grunt/UglifyJS