Implemented helper routines to assist in cueparameter parsing

I've provided 2 routines (token_in_list and find_token) which search for or return the index of a token in a null-terminated array of tokens.
    
These routines are helpful for providing a general way of parsing a given sub-grammar in a very general way that can be shared by several different users (Such as cueparameter parsing for the 5 parameter kinds)
    
This code was originally taken from #73, but has been modified and moved into parser_internal.h so that unit tests of these helper functions can be written.