WIP.
Do not create a message when:

When an existing item is updated within 6 hours after the initial insert
by the SAME user.
CFD-151- Activity stream tests
Merge remote-tracking branch 'origin/develop' into feature/CFD-193-Activity_stream_insert_update_messages
WIP for node_access_acquire_grants(), but in the end we will handle it on og.
Comments messages fixed.
Changed message creation and updating conditions.
Made general functions for insert_node and for update_node.
Code moved to pluggable_node_access.
Update.
Tests updated.
Comments. Tests are updated.
Use forked version of OG.
Use the right branch.
Start adding logic to components.
Feature/cfd 185 187 fix apache solr on travis ci
Merge branch 'develop' into 196
Added page Discussion edit.
Panels dependency.
Don't show selection of node types. Show discussion fields.