* refactoring
* headers forwarding
* now PING requests CAN contain headers
* couple of RPC tests
adding tests for basic, push and ping messaging
Merge branch 'master' of github.com:wookieb/zorro-rpc

Conflicts:
	src/Wookieb/ZorroRPC/Client/Client.php
	src/Wookieb/ZorroRPC/Serializer/SchemalessClientSerializer.php
	src/Wookieb/ZorroRPC/Serializer/SchemalessServerSerializer.php
	src/Wookieb/ZorroRPC/Serializer/ServerSerializerInterface.php
	src/Wookieb/ZorroRPC/Server/Server.php
	src/Wookieb/ZorroRPC/Transport/Request.php
	src/Wookieb/ZorroRPC/Transport/ZeroMQ/ZeroMQClientTransport.php
	src/Wookieb/ZorroRPC/Transport/ZeroMQ/ZeroMQServerTransport.php