Primarily an attempt at restructuring the plugin logic

I'm digging into making Clef work better with multisite this week and decided that before I could do that, I needed to make this code a little more usable.

This is my first attempt at doing that. I tried to follow a structure similar to the one @daveross and @10up use, but I also took some influence from the Jetpack plugin (with the whole class.<thing> naming structure primarily).

This restructuring also adds Grunt for build processes and switches from standard CSS to SASS (although, at the moment, we have 0 styling).

I would *really* appreciate feedback on whether this structuring of code makes logical sense — especially with regards to where I do hooks etc. 

@lolux @daveross @samhotchkiss @anyonelsewhocares

Also, as of right now, the plugin seems stable on this branch, so I'd appreciate it if anyone would put it through the races on a test or personal site (restructuring freaks me out).