Update reset session cookie logic.

Updated the reset session cookie logic to add the new cookie specifically to the instance host, rather than the blanket .salesforce.com URL.  Fixes some oustanding issues with the broad setting of the sid cookie, as well as not setting on the right domain for Trialforce orgs.
Bumping patch version
Merge pull request #509 from khawkins/session_cookie_on_instance

Session cookie on instance