Remove backwards compatibility hacks for old libraries and Python versions
Remove broken-looking and unneeded time.timezone hack

What happens if the hours being subtracted are on different days?
Remove code that used the “rexec” and “Bastion” modules

These modules were apparently broken since Python 2.2 or 2.3 and no longer
exist in Python 3.

* Most of the SafeTkinter module usage was commented out
Remove support for passing attributes as a list object