Bugfix: refresh courses thread now exits when done
Restore default sys.stdout
Use myStream_message function to add text to "status"
Remove old comments from LoginThread
Connect ok/error signals to both login status and status textbox
BUGFIX: correct behaviour when refreshing courses

Before this fix, the "ok signal" from loginthread is not disconnected
from do_refreshcourses; therefore, the next time the user presses "try
login credentials", the function do_refreshcourses gets called.

The function do_refreshcourses should be called only when the ok signal
is emitted from the loginthread started by refreshcourses.
Test script: test only useful files
Fix typo in filename