Tweak to Empty init file assembler

Now creates files in correct sub-directory
Ignore .bak files generated by Quartus editor
Re-work after second thought

better naming
factored out MLAB memory
notes for later fixes (grep for "ECL XXX")
Reworked Addressing parameter generation, and generation overall

Place generated parameters into common_values
Passed-in parameters override generated values at correct points
Re-work of default offset Addressing. Needs testbenching.

Min/Avg/Max Fmax: 453/490/520
For now, D offset is 12 bits, though only 10 are really needed