Getting Started improvements

* Add Activator templates as the default path
* Replace the dependencies section with info on how to add Slick to an existing app
* Remove reference to example code (Note: We could possibly add references to the code in the Activator template but I'm not sure yet how that would work best.)
add slf4j and slick examples
Merge remote-tracking branch 'refs/remotes/origin/pr/579'

Conflicts:
	src/sphinx/gettingstarted.rst