added support for ticket metrics
Merge pull request #17 from carlfredrikhero/patch-1

added support for ticket metrics
[doc] added ticket.listMetrics
Merge pull request #20 from Ignigena/master

Fix batch ticket action, add batch delete
[doc] added ticket.deleteMany
[fix] removed local declaration of result conflict
[fix] return error on empty result

This avoids the error of the form Cannot read property X of undefined
closes #15 #18 #19
[bump] new release
Prevent errors when last_element is a number.