ServerParams should contain the server state and not information about
client settings or capabilities. Move those things up a level to the
CConnection object.

No need to have one setting for each extension. All the client code
needs to indicate is if it supports resize. The common code can then
map this to relevant extensions.

These were either completely unused, or always true.

We need to track different things in the server and client, so
separate things to two independent structures to keep things more
clear.