lang: Fix arg counts to include return value

lang: Pass NULL values to calls first instead of later ...

This looks a bit awful right now but will be important later on
when we add proper support for calls in bytecode.

lang: Put return value as new args ...

This avoids the dispatch having to free values.

lang: Remove unused references to stdio.h

lang: Use static qualifiers for internal functions and data

lang: Return values in args ...

This allows multiple return values which makes things a lot easier.

lang: Implement classes