Raise exceptions when no entrypoint, macro or template found

When generating XML and no component is found for the given yaml entry
whether it is a JJB module, macro or job template, raise an exception
instead of silently continuing by not generating XML and requiring the
user to check the results.

Change-Id: Icd4b1fae123c8bbb4d8af7aa14522251cd9cf8d5
Added support for Stash Notifier

Change-Id: I1e3e95a152de116df62b9124a50e845bc026f608
Ensure jobparams and group_jobparams are dict

When defining a list of jobs in a project, if a colon is added after
the job name but no parameters is provided, jobparams is None.

As dict.update() expects parameter to be iterable, ensure jobparams
and group_jobparams are always a dict to prevent JJB from crashing.

Change-Id: Ie57aa9e5b446fe502dff896cde773ddcc92ba803
Closes-bug: #1253180
Merge "Ensure jobparams and group_jobparams are dict"
Merge "Added support for Stash Notifier"
Merge "Raise exceptions when no entrypoint, macro or template found"