Rename watch buttons according to the spec

D -> E; Light -> D
Add Sched class to manage the main loop
Move displayUsage() impl to .cpp
Add debug fsm transitions trace
Add time set mode draft
Increment time on demand only

Press spacebar to simulate 1 sec.
Clear screen before each cycle
Refactor Makefile

Separate compiler args into variables
Add libboost-program-options1.48.0 to provisioning
Add command args facility

Add command args using Boost.ProgramOptions. Add only debug FSM flag for
now.
Move clear screen into Display method
Remove on-demand progress; make sched more precise

Sched issues a frame() to Input each 33.3 msec, to Watch once per
second