Duplicate ram labels in output sym file

[H-A-M-G-E-R]

makes sym file much larger than needed

[CharlesVanEeckhout]

ok i have a solution

when all the ram labels will be enum, i can assemble the constants_ram as a separate object file

in linking, the ram vars will be exported once to the bank object files, as opposed to multiple times by each bank object file, so that will eliminate the ram duplicates

[CharlesVanEeckhout]

this wont work anymore bc of commit 1ae9432 for #55

the assembler wouldn't treat the ram labels as constants anymore, so it could not evaluate their value to auto-assign operand size