[WFLY-3603] Add global resource notifications

Runtime attributes does not store their values in the resource models
and their read handler must be called before and after their write
handler to get the old and new value of the attribute.

JIRA: https://issues.jboss.org/browse/WFLY-3603
Merge pull request #62 from jmesnil/WFLY-3603_runtime_attribute-value-written_notification

[WFLY-3603] Add global resource notifications
[WFCORE-33] Correct http-upgrade parsing with respect to 1.x and 2.x schemas.
[WFCORE-35] Take schema version into account when parsing jvm element.

Also single entry point to JvmXml.java to allow single point for a version switch.