Keep dependencies when returning a CI stated change to review

Returning a change to 'review in progress' (NEW) state from any of CI
states (STAGING, STAGED or INTEGRATING) deleted links to ancestors.
Obviously these dependencies must stay in this case, so ancestor links
are not removed anymore.

Task-number: QTQAINFRA-871
Change-Id: I43617c5ad698121b7b571f86f02784f42d7ec24c
Reviewed-by: Oswald Buddenhagen <oswald.buddenhagen@digia.com>
Hide the "defer" button if a change in state INTEGRATING

The "defer" button was incorrectly visible for a change in state
INTEGRATING. Now the state of a change is checked and deferring
not allowed in state INTEGRATING.

Task-number: QTQAINFRA-889
Change-Id: I6c4134098f875e19e85eb0c6e7b291557952cadc
Reviewed-by: Oswald Buddenhagen <oswald.buddenhagen@digia.com>
Offer "deferred" in search autocompletion box

Search autocompletion box was missing "deferred".
Now following two choices are offered:
* status:deferred
* is:deferred

Change-Id: I81e68b21bc7762437f6970b96f2ec85d69aa06e3
Task-number: QTQAINFRA-893
Reviewed-by: Oswald Buddenhagen <oswald.buddenhagen@digia.com>
Disable 'Syntax Coloring' by default

Task-number: QTQAINFRA-901
Change-Id: I2537db4b00b5b76b5fb272b74eac6009ec2e71a4
Reviewed-by: Oswald Buddenhagen <oswald.buddenhagen@digia.com>