Functions are successfully called, read more

Return keyword is not yet implemented.

Functions are untested.

See #163

source/toy_opcodes.h

@@ -10,6 +10,7 @@ typedef enum Toy_OpcodeType {
 	TOY_OPCODE_ASSIGN,
 	TOY_OPCODE_ASSIGN_COMPOUND, //assign to a compound's internals
 	TOY_OPCODE_ACCESS,
+	TOY_OPCODE_INVOKE, //for calling functions
 	TOY_OPCODE_DUPLICATE, //duplicate the top of the stack
 	TOY_OPCODE_ELIMINATE, //remove the top of the stack