[WFCORE-60] Support multiple registration points for the same capability or requirement

Ease of use thing for cases where the add/remove handler for a type=* resource is the logical place to register/deregister a capability or requirement. We allow multiple registration points to account for the fact that the handler may be executed multiple times for different concrete addresses. Otherwise the subsystem author needs to track how many registration points exist and only register once and only deregister when the last registration point is removed.
Don't try to get service and to reconnect during server shutdown(HostControllerConnectionService is stopped)
Merge pull request #291 from bstansberry/cap-req-multi-reg

[WFCORE-60] Support multiple registration points for the same capability...
[WFCORE-253] Enable the use of expressions for sasl-protocol and server-name.
[WFCORE-256] Remove comment saying Kerberos is only for HTTP.
https://issues.jboss.org/browse/WFCORE-145 CLI run-batch command cannot process files with comments or blank lines
[WFCORE-257] Remove TODO comment to add access constraints as these attributes are already contained within resources flagged as being MANAGEMENT_INTERFACES.
[WFCORE-259] Update realm readiness checking to be based on having at least one mechanism ready for challenge/response style authentication.
Merge pull request #335 from darranl/WFCORE-257

[WFCORE-257] Remove TODO comment to add access constraints
Merge pull request #333 from darranl/WFCORE-256

[WFCORE-256] Remove comment saying Kerberos is only for HTTP.
Merge pull request #332 from darranl/WFCORE-253

[WFCORE-253] Enable the use of expressions for sasl-protocol and server-name
[WFCORE-210] make deployment scanner treat listFiles() returning null correctly as error case.
[WFCORE-60] Log boot capability validation issues
If -secmgr is passed as a server argument, it should enable the security manager.
[WFCORE-258] Import services from the WildFly Security Manager to allow jboss-modules to install the security manager.
[WFCORE-258] Add a property to pass server arguments to a test domain server.
[WFCORE-258] Add ability to enable the security manager with the security.manager system property.
Add the ability to force begin requests to the ControlPoint

This allows threads that are alredy running to use an
executor service or asyn method without it being rejected.
[WFCORE-213] :  Clean unreferenced items from the content repository

Now we are using ContentReference to track contents in the content repository.
Now we are tracking references to overlays.
Trying to use server group definition for domain mode.
Simplifying ContentReference
WFCORE-211: Fixing overzealous cleaning of HC content.
[WFCORE-178] :  ContentRepositoryImpl should not call File.deleteOnExit when deleting content.

Using the new Path API instead of File.
Cleaning empty old directories.