Added Grunt handling

The concat and uglify modules are used to place FullScreenMario.js and
FullScreenMario.min.js in /dist. Default files are renamed to index
files to represent where they belong.

Also fixes a few errors with UserWrapper from the last few commits,
whoops.

Partial fix for #56 - will have to automate .css files and the move from
index-dev.html to index.html.