TweetTest , now has tests for isTweet and getLifeTime (partial)
finished tests for getLifeTime() 
and added some tests for checkAndSetLastTime()
added another test for CheckAndSetLastTime()
test not working, probably some build-path or other IDE related problem
fixed a bug in function CheckAndSetLastTime
After function was supposed to be Before.
tests are now running, some are still not implemented
removed unnecessary import
fixed some JavaDocs
deleted unnecessary tests.