Cleaned up pixel drawing method
Updated comments (reminders)
New comments; new constructor variant stub
New constructor variant
Rename lockCanvas, unlockCanvas to Lock, Unlock; mustLock is private now
New method valid
Rename of method freeCanvas to destroy
Updated comments
New method valid
Unlock method is now void of return
Additional ERR checks
notes
Updated makefile for solo builds, in addition to existing hierarchy
Cleaned up header file deps
Bit of additional ERR checking (asserts)
New argument param elapsed_time on GameState(s) Update method