Remove send message gravity for RtL

Change-Id: I6ef122632a2c098054babad2baaa6cd338dc96b8
Locate the timestamps outside of bubbles

Change-Id: Ib6739976a65333a908027b5a88cd848f3459fe01
Shrink the minimum bubble size

Change-Id: Ic639df7b72dbbe51859a1d44a5a38fc4f0ef9e5a
Fix timestamps layout_width

Change-Id: I71d1de6364ecef7d05dd4d07bddc4bcf25b8d1a2