A packet that allows a client to set filter attributes

Currently the metaserver responds with ALL listed servers, this packet will register an attribute to narrow the search criteria.

NMT_CLIENTFILTER Anatomy:
4 bytes ( packet type )
4 bytes ( length of attribute NAME )
4 bytes ( length of attriubte VALUE )
X bytes ( NAME ... ie FOO )
Y bytes ( VALUE ... ie BAR )

This will essentially register filter "attributes" for a client connection ( a connection is a client that has performed the 3 packet handshake, and has a registered "client session" ).

These attributes will be later used in a context sensitive LISTREQ.