Fixed some error states and error messages, read more

By leaving 'null' on the stack, it won't cause stack underflows in a
bunch of erroneous situations. This will allow the repl (and other
situations) to continue if they want to.

I've also fixed some error messages in toy_table.c, which were formatted
badly.

Closes #162

source/toy_vm.h

@@ -39,8 +39,6 @@ typedef struct Toy_VM {
 	//easy access to memory
 	Toy_Bucket* stringBucket; //stores the string literals
 	Toy_Bucket* scopeBucket; //stores the scopes
-
-	//URGENT: panic/failed state flag
 } Toy_VM;
 
 TOY_API void Toy_initVM(Toy_VM* vm);