TimeStripper, tzoneFixedOffset are now in pywikibot.textlib

This should solve the deadlocks during tests. This was caused by the

Site = pywikibot.Site()

in the import scope of archivebot.py. Calling Site() causes network
communication, which causes deadlocks if this happens during test
loading. During test execution is OK (obviously)

Change-Id: I11d74247613bb16974c883b192e5fc8f90ffd6e5