rx click tune using globals resulted in a cleaner design although I would prefer...

rx click tune using globals resulted in a cleaner design although I would prefer not to have used globals.  Maybe passing the address of the freq offset in the waterfall/spectrum constructor would have ben cleaner

git-svn-id: https://svn.code.sf.net/p/freetel/code@1042 01035d8c-6547-0410-b346-abe4f91aad63