[BUG]SROM Font: Corrupted '@' and '{' characters #16

SROM contents and ng_text C code are betraying the reader. ng_text promises to display all characters in ASCII table, but it doesn't. I think it is assumed by design as build-srom.py script is erasing tiles at '@', '{' and 0xFF positions. I suggest to remap characters in SROM in order to fit hardware constraints:

• empty tiles at '@', '{' and 0xFF positions
• avoid MAX_330_MEGA and PRO_GEAR_SPEC positions