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.
Thanks for your opinion! Yeah, agree that it makes code more complex. Probably in this particular case it's better that we remove event handler right after user clicked on the item (but still, it's not a big performance benefit anyway).

Ok, I'm glad that we cleared that up, so let's keep code simpler by leveraging more "markup-defined" elements as you suggest. And only in case we have performance problems in the future because of this (I hope we won't :)),  we can reconsider the way we're managing DOM.

Also I'll check if I can incorporate ```documentFragment``` into contact renderer without risky changes, and do it if it's so :)