Link stats

Ticket: https://jira2.iparadigms.com/browse/TRN-123

Couple notes:

1. I used Terry's ruler trick to add a 120 char-wide ruler in my editor. Consequently, I wrapped several lines in this patch (<10), so be aware of that.
2. I fixed the behavior of addDomainWithExcludeReason (in dispatcher.go) so that if you pass an exclude reason to it, and the domain is present, the exclude reason will be correctly updated in Cassandra.
3. Removed GetStats from cassandra.DQ as it's utility seemed lost now that the count-stats where a simple cassandra read.

Updated docs.