changed how rpn token lists are compared, corrected memory leak

the token comparison was changed to only compare the code, sub-code
(for only the program codes), and the string of the token using a
case insensitive comparison except for the Rem, RemOP and ConstStr
codes

the rpn item comparison was changed to only compare the token and the
attached count; it is not necessary to compare the attached tokens
since these only reference other tokens in the list, which will be
handled when the token of the other items are compared

when an replaced line rpn list is the same as the existing line rpn
list, the rpn list is not used and therefore needs to be deleted
(this corrects a memory leak)