Currently the error reporting is rather lacking.

It would be nice to have expressions be implemented in reverse polish notation for now for simplicity's sake...
but maybe one day if there is a demand we can introduce a directive that will allow infix expressions such as .exprinfix
and .exprpn.

The current assembler has a hard-coded definition for SM83 which is fine, but it should be possible
to make it more platform independent without too much work since the opcodes are all in a table already.

A disassembler should have the following features:

• Allow partial disassembly of an input file
• Display a call graph
• Generate symbols on the fly for all jumps and calls
• Allow definition of symbols ahead of time
• Output labels where jumps occur

Label scoping should be simplified to simply add the global label's name to the locals.

e..g

glabel:

.llabe1: ; this becomes glabel.llabel

When resolving expressions, keep a list of unresolved names and attempt to resolve at the following points:

at the end of a scope -> if this fails add to the global unresolved list
at the end of the program -> if this fails we have an unresolved symbol

We should allow jumping to unnamed labels using some relative label syntax such as:

jp +
jp ++
jp -
jp --