fix bugs with errors being propagated

also re-implemented execute_ref and add REF_REG macro
remove return statements in void functions

these functions return void, so shouldn't return anything
first bit of work to use libuv for console

doesn't work and everything yet, but it's an outline of how it will work
swap the 0x0080 bit b/n primary & secondary regs

primary can now be accessed from C functions w/ a plain integer.
this should reduce the chance of bugs from forgetting to use PRIMARY_REG(x)
fix some forking bugs

still doesn't work quite right yet