use obo-label-names in sentences as well

This is solved by just calling set_display_text! on the
sentences at the right time (after the display_name for
the symbol has been updated).
add migration to update display_text of obo

Add the migration the update the display_text
of already existing obo sentences.
set displaytext in sentence only if non-nil.
optimize set_display_text! body.
improve conciseness of the obo-text migration.
use start_cluster rake task for elastic test

This will allow for a longer bootup-time before
a timeout.
add a script to rebuild ontohub in development.
add invoker-support to rebuild script

This includes aborting if invoker ist not installed and
restarting a running invoker instance, or starting a new
one if no one was running before.
set ontologies correctly for global/local.
extract search-response display into own partial.
display default ontologies inside of repository.
move ontology-search partial to ontologies

Actually the partial is not shared between controllers. Only the
OntologiesController uses it.
let search controller use partial in ontologies.
Remove unused columns from sentences.
Add first draft of Theorem and ProofStatus models.
Exclude Theorem from Sentence scope.
Add Theorem route, controller and view.
Add ProofStatus model, remove STATUSES Constant.

The ProofAttempt and Theorem models now rely on this new model.
Add colored label to ProofStatus.
Add Popover for ProofStatus.