This allows us to a) compile the coffeescript and sass from xmodules
using the new out-of-band method and b) reload xmodule static content
whenever it changes, which should make devs much happier.

The unused styles are referencing images that no longer exisit,
breaking collectstatic and therefore tests.

scss files that were still being partially used by the current
discussion forum.

This reverts commit 010bccc8.

This reverts commit 793354a0.