Log Message:
Update to dvtm-0.5.2 (patch from maintainer in private mail).
While here set a proper LICENSE (dvtm is under MIT/X license).

Changes:
 o compile fix for Mac OS X
 o optional beep on terminal bell (enable it per window with MOD+B)
 o the whole screen redraw command which is now by default associated
   with MOD+r reads the terminal size and adjust the working area
   accordingly