Suggestion: Adjust #DEFINE macro a bit - #DEF and comments

[AnFazer]

Two simple, low-priority enchancement suggestions:

1. Allow to use the more assembler-like #DEF in place of the C-like #DEFINE, to better fit in with the instruction syntax and to reduce time spent typing. The old one remains usable.
2. Allow to use comments within the DEF macro, to allow for commenting on defines themselves on the same line: #DEFINE .IN UP #DEFINE .NEXT DOWN #DEFINE .RH LEFT #ROM HIGH #DEFINE .RL RIGHT #ROM LOW #DEFINE =IT 5 #CHAR LOOP ITERS