Tweak: .gitignore .DOFF files.

Will need updating later when each memory has its own init file
Updated hailstone testbench for default offset. Tested. Works!

Min/Avg/Max: 464/491/517 (basically, 491 MHz +/- 5%)
Currently only implements one common default offset file for A/B/D
No programmed offsets, so you have to inspect the ALU output, no I/O
Brought back hailstone check program