Removed bootstrap and angular-motion dependencies from bower.json

Per projects description, there are no external dependencies other than Bootstrap.css.
Yet currently anyone that installs angular-strap via bower is also forced to install angular-motion(optional) and bootstrap(which is less driven). Some people may want to skip angular motion and some people will want to use bootstrap-sass for their workflow.
This PR moves angular-motion and bootstrap to the devDependencies setting which still lets you use it for a development flow(and viewing docs), but also allows people to ignore these packages for production flow.

I confirmed that all the tests pass and gulp serve does server the docs