Improve handling of codepage related code

Issue #13 resolved
Vasyl Zuzyak repo owner created an issue

Note: this makes sense untill new build will introduced

items to do:

  • add new global variable 'last used codepage' (like output.file)
  • if its required supply something like changeCodepage flag for create-target-file target call(s)
  • implement logic inside create-target-file target