Two changes:

Two changes:
- support scrolling of message window;
- simplify the code for creating a message window,
  and try it using a second one in the top of
  the keypad (where we echo the dialed number).

The 'skin' that supports these two windows will be
committed separately.

git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@97530 65c4cc65-6c06-0410-ace0-fbb531ad65f3