INT-2915 JMS Remove Deprecated Attributes

delivery-mode was deprecated (in favor of delivery-persistent)
in 2.0. Remove attribute from schema and parser.

Unfortunately, the setter on the gateway was never deprecated
so there is a possibility someone is using it programmatically,
with no knowledge that it is going away.

Deprecated the setter.

Also, added schema documentation for several attributes where
no documentation was provided.
Merge pull request #731 from garyrussell/INT-2915

* garyrussell-INT-2915:
  INT-2915 JMS Remove Deprecated Attributes