Add words to write to interrupt vectors

[tkers]

There currently is no (nice) way to write interrupt handlers.

Workarounds for now would be to:

• Manually write bytes in the $0000 - $00ff range using c!
• Get the ROM offset with here and force emit code after setting the offset with ==>

A possible improvement would be to implements words like :interrupt1 (or the equivalent for code) that emit the definition/asm to the correct address.

[lf94]

I really like the suggestion to auto-map words to the correct places. The primary thing is the documentation needs to be clear about it, and maybe we call them by their documentation names aka RST0, etc.

We can even trigger an error if code overflows into another interrupt during compilation right?