Cleanup, use "linecache" module to read source code for tracebacks.
Cleanup, use "linecache" module to read source code for tracebacks.

* May be more correct, or more portable, and least it's more obvious. We
  do not need the caching feature, but it doesn't harm us.

* This solves a TODO.

kayhayen/Nuitka,wfxiang08/Nuitka,kayhayen/Nuitka,wfxiang08/Nuitka,tempbottle/Nuitka,wfxiang08/Nuitka,wfxiang08/Nuitka,tempbottle/Nuitka,tempbottle/Nuitka,kayhayen/Nuitka,kayhayen/Nuitka,tempbottle/Nuitka