Incorporation of assembler into build steps

[CTalkobt]

So, to implement the '@' I'm thinking of using the get_mem, set_mem calls to cache a pre-determined location, upload a program to it, execute it and then restore memory afterwards.

I'm thinking this "on-machine execute" could be abused for other things in the future, so will make it it's own function.

I'd like, however, to include the 6502 .asm file as part of the build, rather than the .prg blob. Any preference on the assembler used?

[gurcei]

Sorry just was the issue ticket here now, I guess acme is a pretty popular assembly compiler choice within the mega65 project these days, maybe go for that.

[CTalkobt]

Changed title to track effort separately from the '@' stuff I'm doing. There's some existing small assembly currently being used that can serve as a validation point.