Add Sass compile

Change-Id: I27d2e3f634b6a22f36d20d80169be07ed0a1ff19
Add dropdown control

Here we're implementing a simple internal directive to power the
dropdow. This might be overkill, but it could easily be subbed out later
or replaced by a user's custom template.

Change-Id: Iff62343d9ae56ec3daec3136ab9243e15f535cf6