Restructure Angular app into CommonJS modules

Signed-off-by: Alex Coles <alex@alexbcoles.com>
Bundle CommonJS modules with Webpack

Minimal work necessary to make Sprockets and existing Karma tests work
with Webpack.

Signed-off-by: Alex Coles <alex@alexbcoles.com>
Fix stray global in Karma tests

Signed-off-by: Alex Coles <alex@alexbcoles.com>