Demo converted to unit tests; bug fixes
Demo converted to unit tests; bug fixes

PyGameMakerCodeBlock's now know how to load() and run() themselves.
 load(): exec functions and executable sections into their
  module_context __dict__
  Takes a list of modules to be imported
 run(): module_context.run()
  Takes a symbol table argument
Fix clear() that was not resetting the object properly.
Fix lost else blocks.

rlc2/pygame_maker,rlc2/pygame_maker