Improved checks, added leaderboard functionality

Improved already_replied() - logging in is not case sensitive but python
is. Forced check to lowercase

Improved scan_comment() - same as already_replied()

Improved scan_comment() logging.info. Now gives a link directly to the
comment. This is more useful than the comment name.

Leaderboard functionality - Clicking on the deltas awarded now takes the
user to their wiki page where all of their deltas are listed.