MDNR:

MDNR:
- removed init() method from mysqlnd_conn_data and moved the initialization
  to the object factory->get_connection(). Now it is unified as with the prepared
  statement which doesn't have any init() method
- the protocol decoder factory now takes connection as parameter at creation and
  thus there is no need to pass the connection as parameter when calling the read
  or the write method of a packet.
- saved the protocol payload decoder factory as pointer in every packet (read/write)
  so the connection doesn't need to be passed on every call of read/write (dependency
  has been already injected at creation). This will alow to move protocol specific
  code from MYSQLND_NET (send_ex()) to make MYSQLND_NET leaner and free from protocol
  stuff.