Added parsing of table literals

Modified assignment and adding opcodes to also keep table on stack
Created concrete definition of VM opcodes

Moved to 5 bit opcodes. This lets all the nescessary functions
be implemented rather succicntly and leaves room for additions later.

Currently bytecode is passed around as bytes containing the 5 bit
opcode and 3 flags for helping code generation. More info is specified
in `vm.h`.