Bug 1354: Added rpcReplyToDomNodes method.

Added rpcReplyToDomNodes method into XmlDocumentUtils to convert XML Payload from Rpc Reply message into
Composite Node structures.
Added test and test files (schema, test payloads) for rpcReplyToDomNodes method.

Change-Id: I45e01d58689ad448cdf6e8541cb680db62667d7c
Signed-off-by: Lukas Sedlak <lsedlak@cisco.com>
Merge "Bug 1354: Added rpcReplyToDomNodes method."