adding a command-line utility for executing common testing functions
missing delete function on config.
new katest management command "clean_db"
preventing central-server regret

Conflicts:
	kalite/management/commands/katest.py
refactor confirm logic in katest clean_db

Conflicts:
	kalite/management/commands/katest.py
creating securesync subapps.  biggest hacks: having to define empty Meta class on *any* subclass of SyncedModel, doing weird Device stuff in engine.models to avoid circular imports
adding back crypto_login, ROOT_UUID_NAMESPACE in settings is hard-coded and not overridable, small (test) bugfixes to get tests running.
adding missing import
Merge pull request #502 from bcipolli/securesync_subapps

IDOC: Securesync sub-modules
Merge branch 'release-0.10' of github.com:learningequality/ka-lite into release-idoc

Conflicts:
	kalite/securesync/api_views.py
two small (but major) bugfixes
Merge branch 'securesync_subapps' of github.com:bcipolli/ka-lite into release-idoc
Merge branch 'release-0.10' into release-idoc
Merge branch 'release-0.10' of github.com:learningequality/ka-lite into release-idoc

Conflicts:
	kalite/management/commands/katest.py
	kalite/securesync/models.py
	kalite/securesync/views.py
Merge branch 'release-idoc' of github.com:learningequality/ka-lite into develop