first pass implementing 'paths' for video and exercise objects in node_cache.
Updates to make topic updates more robust.
Merge remote-tracking branch 'upstream/develop' into multipath_node_cache
Merge pull request #192 from bcipolli/user_logs_syncing

User logs syncing (resubmit)
add comments, rename functions to be more readable.
Merge pull request #215 from bcipolli/multipath_node_cache

Multipath NODE_CACHE
Merge remote-tracking branch 'upstream/develop' into install_with_zone

Conflicts:
	kalite/main/views.py