Fix incorrect cvar names in comment

The "gun_x", "gun_y", and "gun_z" variables are now "cg_gunX", "cg_gunY",
and "cg_gunZ". Reflect this change in a comment in cg_view.c
Implement /flag, /unflag, /flaglist (from Aardvark).

This requires a ‘misuse’ of the admin command table. Command entries with
NULL command names are command flag entries, documenting which commands use
which flags via G_admin_permission() (such use is listed in green).

Also, it has to handle the difference between NULL and "" (flag names): NULL
means no flag, but "" is the flag name for internal-use commands (and is
thus unavailable).
Tidy a little cvar-setting mostly-duplicate code; fix parameter count handling.
Move .pk3/.pk3dir count reporting after filtering.
Fix poison display in the default alien HUD.
md5sum should be checking in binary mode.

Not an issue on GNU/Linux ☺
Put admin commands back in the right order.
Fix recent problems with admin command parsing.
Sort out adminhelp command listing issues.
move optional command prefixing out of con_tty and con_curses to a later shared point

Main intended change is to carry the information of the commandprefix's existance on to a later location in the code
and to not add an enforced prefix anymore to history if it wasn't used

Unintentionally the whole thing should now also enable the win32 console to do the same.
adding com_consoleCommand which sets the default command that gets used for text entered into the consoles
this works for ingame as well as outgoing consoles

an empty value will make all entered texts executed as commands direclty
by default it's set to "say" for the client and is empty for the dedicated server
Use memcmp instead of self-built while loop
add a few lines of documentation to com_consoleCommands code
fix wrong socket ID comparison
Print “execing …” only if successful.
/execq – execute a script without notification.
Don't include client.h in sdl_glimp.c as it is part of the external renderer lib.
Fix restoring fs_game when default.cfg is missing.
Change more operator commands to require sv_running to be usable. Patch by Ensiform.
Fix a few comparison off-by-ones.