Exclude things during .deb packaging correctly, so that we don't have a bunch of build detritus left over. FPM still leaves the empty directories, unfortunately

Use a key function that is safe for use w/ memcache

This is needed for the asset-pipeline. The pipeline has to map a requested asset name ('css/application.css') to a string that encodes the file contents ('css/application.12323423abcf.css'). It caches these associations in memcache. We have the potential for filenames with spaces in them, which memcache can't handle, so we need to escape the cache keys in such a way that memcache can handle them.

It puts these in a cache named 'staticfiles' (http://django-staticfiles.readthedocs.org/en/latest/helpers/#cachedstaticfilesstorage). In the future, it may make sense to put that cache onto the filesystem, rather than memcache, but we should do that only after performance testing.

Url encode memcache keys, rather than writing a new encoding scheme. Also use fasthash, rather than md5

Asset pipeline

Split the pipeline_mako templates from the namespace used by actual django-pipeline django templates

Conflicts:
	static/js/application.js

Add newrelic handler, rather than custom function to log exceptions

Adds ARIA labels to navigation

This includes calculator open/close button, navigation, profile, and
book's table of content.

First part of courseware refactor