Major re-work of the comm frequency storage and lookup. Only a small core amount...

Major re-work of the comm frequency storage and lookup.  Only a small core amount of data is now stored instead of the whole ATC classes.  All the comm frequency types are now stored in one map instead of a map each.  query(...) and query_bck(...) have been renamed to FindByFreq(...) and FindByPos(...) for clarity and consistency with NavList