Change providers: minidom to elementtree + check_auth

+ PEP8 clean up
+ function clean up
+ logger.log unicode
Rename omgwtfnzb variables to follow naming pattern

+ catch for empty username/apikey.
Convert old omgwtfnzb variables to new + save config after migrate

+ sync backup number with config version
Replace BTN deprecated getTorrentsSearch with getTorrents
+ added proper initiated by: @genial123
+ minor tweaks and fixes
Merge pull request #713 from itofzo/change_and_cleanup_providers

Change and cleanup providers