Bug 1034600 - [Messages] Suggestions list is badly located. r=julien

* Recipient suggestions container moved to more appropriate place;
* Recipient suggestions now occupy all possible space minus heights of the app header and message "To" field.
* ```.contact-list``` styles are cleaned up a bit.
But it still will consume some memory (tiny, but if we sum up every such handler....). In other words I have a rule, if I can easily unsubscribe from event handler that is not needed, I do it. Do you see any drawbacks ?