Temporary fix for a strange tag cloud bug

Tags appeared several times, with the count split among them
E.g. lol(5) and lol(7), and if you click on lol,
you'll see 12 items.

This patch aggretages them (not a heavy operation),
but I wonder how this should be done properly.
Merge pull request #30 from thedod/weird-tag-fix

Temporary fix for a strange tag cloud bug