Introduce sendIntercomUserData and sendIntercomTag

xref scraperwiki/swops#17 scraperwiki/swops#18 scraperwiki/swops#19
Fix copy/paste error.
Make incrementing intercom values work.
return undefined lest xdm return our entire $.ajax object!
Merge pull request #494 from scraperwiki/20131217-reporting

Introduce sendIntercomUserData and sendIntercomTag