[AS7-6334] add expression testing to the messaging subsystem

* convert the messaging transformers to the new builder API
AS7-3208 re-format help content to the max line length of 80 chars
AS7-3208 format generated help content for generic type commands taking into account the current terminal width
[AS7-6120] testcase on support for system property substitution
AS7-6436 tearDown methods of ServerSetupTask should be called in reverse order to avoid service dependencies problems.
[AS7-6434] Reject resources. Similar to discard but gives an error/warning.

Make the discard and reject checkers created from the builder recursive
Get rid of unused TransformationPolicy
Add reject transformers & tests for mail subsystem
Make mail legacy subsystem not persist xml
WS reject transformers and tests
Don't throw error in OperationTransformers on "way out", the host might have changed their ignores after the initial registration
Throw OFE during resource transformation for non-ignoring 7.2.x slaves
Include host name in the resource transformation exceptions
Null check for channel, based on NPE at http://jenkins.mw.lab.eng.bos.redhat.com/hudson/job/JBoss-EAP-6.1.x-Community/50/testReport/org.jboss.as.test.integration.domain/AdminOnlyModeTestCase/testAdminOnlyMode/