When closing issues, we were using a malformed format string.  The 's'
from the '%s' was missing.

Signed-off-by: Malf Furious <m@lfurio.us>

The 'iss-mesg-add' form now handles when the 'assIssue' submission is
sent.  This is the only submission of this form that looks at the
(usually hidden) 'assignee' dropdown field, which has been made a
required field however.

Signed-off-by: Malf Furious <m@lfurio.us>

Handler now includes logic for optionally advancing the issue through
the pipeline.  If this happens, 'closeIssue' (for example) will not be
checked, as only one submission can be used.

Signed-off-by: Malf Furious <m@lfurio.us>

I was failing to assert user has modify permissions for the issue.

Signed-off-by: Malf Furious <m@lfurio.us>

The 'iss-mesg-add' form will now allow a mesg to be omitted, since it
will also be handling other events.  These events are part of the same
form since the UI allows users to post a message and trigger these other
actions at the same time.  We now only create a mesg object if a mesg is
given.

Note that an attachment requires a message.  IE:  any attachment is
ignored if no message is created.

Signed-off-by: Malf Furious <m@lfurio.us>

Signed-off-by: Malf Furious <m@lfurio.us>

Submissions to the iss-mesg-add form are now handled by this function.
User must be logged in and permitted to post to the issue in question.

Signed-off-by: Malf Furious <m@lfurio.us>