Fix for creation of new TFS items and better error

fix for creation of new TFS items and better error trapping so an
exception in performing an action based on a LeanKit event does not stop
the event subscriptions from working.
Added support for creating epics in JIRA

This required getting the custom field names and ids from JIRA which is
done through the Custom Fields property. We then set the custom field
for Epic Name when creating or updating an issue.
Merge remote-tracking branch 'upstream/master' into Add-Microsoft-Project