Memory Testing / Minor Memory Leak

Since all of the tests are now working with the new translator (excluding the commands not yet implemented), it seemed appropriate to change the memtestn script to run all of the tests.  After changing this script, two memory leaks were discovered in translator tests #7 (Errors) and #9 (Semicolon Errors).  The memory leak determined to be occurring with sub-string assignment statements that contained an error.

The memory leak occurred because an RPN item was allocated for the sub-string assignment token, which is not appended immediately to the RPN output list.  The RPN item is left on the done stack, which the LET translate routine pops and pushes it's token to the LET stack and then deletes the RPN item.  However, if the next token that should be a comma or equal token is not or a parser error occurred, then this does not occur.  The error clean up code assumes that all RPN items on the done stack have been added to the RPN output list, so only the items in the output list are deleted.

This problem was corrected by slightly rearranging the code in the LET translate routine where if there is an error with the comma or equal token, and the top of the done stack contains a sub-string assignment token (that has not been added to the RPN output list), then the done item on top of the done stack is popped and deleted, which deletes the RPN item and its token(s).  With this change, all of the tests with the new translator have no memory errors.

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