Bug 1003: Restconf - remove whitespace on input

JsonReader, XmlReader:
   - Trimmed whitespace on leaf data input

AbsractRpcExecutor, BrokerRpcExecutor, MountPointRpcExecutor:
   - Modified to handle IllegalArgumentEx and UnsupportedOperationEx
     thrown from invokeRpc to throw appropriate ResconfDocumentedEx.

ResconfDocumentedExeptionMapper, RestconfError, RestconfErrorTest:
   - I discovered that the Response.Status.NOT_IMPLEMENTED jaxrs enum
     is defined in the enum class that is used at compile time but
     isn't defined in the run time enum class provided by jersey.
     So I changed RestconfError.ErrorTag to store the integer status
     code (501) instead of the enum. Ideally compile and run time
     should use the same lib.

- SchemaAwareRpcBroker:
   - Modified to throw UnsupportedOperationEx if no RPC impl is found
     so the restconf front-end can yield the appropriate
     501 (Not Implemented) status code.

Change-Id: Ibfa1dc7ff1526b6d352b9f4e6be2aae0d19ab655
Signed-off-by: tpantelis <tpanteli@brocade.com>