Fix varg generation: generate *_n opcodes with parameters in following meta opcodes
Add stack internal structure: dimanically allocated stack.
Use dynamically allocated memory in parser: every local and global variables are stored in dinamically allocated stacks.
Use dynamically allocated memory in serializer: opcodes are also stored in stack.
Change is_true_jmp and is_false_jmp opcodes to relative.
Change *jmp* opcodes to be able to store opcode_counter_t instead of idx_t.