D3BFG gets the username from Steam, in the GPL release it just
uses the hostname.
Now it's possible to set a custom name with the ui_name CVAR
(like in classic doom3). If ui_name is empty ("") the hostname
is used.
The window losing focus in MP resulted in the console being spammed
with "changing com_pause not allowed in Multi Player" (or similar)
messages. Added CVAR_NOCHEAT flag to com_pause to get rid of that.
If the window loses focus com_pause is set to 1, when it regains focus
it's set to 0.
The behaviour on Win32 stayed the same (the implementation is less
hacky though) and Linux now matchces that.
