Mana-mantis: #506.

Items also have positions, so the ItemComponent only makes sense as part of
an Actor. Later on it will probably be part of an entity that also has an
ActorComponent.

Since it was annoying to update all the places where items were created,
I've introduced a function for this.

The component types are now prefixed with "CT_" because I wanted to introduce
an 'Item' namespace which would otherwise be conflicting. The component types
enum isn't used much in the code so it can look a bit ugly.

Reviewed-by: Yohann Ferreira

If you set net_gameServerName you can now reserve maps in the maps.xml.
There you have to add the servername - property to the <map> tag.
Then the map will only be activated by that server.

Also changed the activate sequence that the account server now tells the game
server what maps to activate (previously the server requested all maps and the
account server said yes or no).

TODO: Fix general inter server map switching.

Reviewed-by: bjorn.

Allows inspection of message data. It is off by default since it consumes
additional bandwidth, but it can be turned on using the net_debugMode option
in manaserv.xml.

Currently the option only affects outgoing data for each host individually.
In particular, enabling this debug mode for the server does not automatically
make the client annotate its messages.

Reviewed-by: Erik Schilling

The timeout remembers a reference point of time against which it can check
how much time is remaining.

Reviewed-by: Erik Schilling
Reviewed-by: Yohann Ferreira