Better visibility for warning about outdated AC version

Commit changes also masterserver URL to AC homepage in info related
to this warning.
fix directory search order

also clarify some log output
(thx grenadier)
added mandatory client log file

- a client will now write all os console messages to "clientlog.txt"
- at every game start, the log file gets rotated (with five old logs kept)
- commandline parameter "-N" can be used to limit the number of lines
  (after the lines are logged, the file is closed)
Fix switching from spectator to active team in bot modes

Before this fix player could switch from spectate to alive mode,
but he stayed in SPECTATOR team.
Note: 2 mouse clicks are necessary to player's spawn. Second respawnself()
is needed, because spawnplayer() is executed before server will switch
player1 to active team, so he would always spawn in CLA base (in bot
team modes).
Fix reset of packages source servers list

Earlier "resetpckservers" command cleared this list, instead of reset
to the initial settings.
Add the clock to scoreboard and change clockdisplay

Commit adds the clock in format mm:ss to scoreboard, instead of
"X minutes remaining" info.
It also enables default the clock on the HUD and adds clockcount variable,
which let to choose between counting forward or backward in the clocks.
Allow to change team while being alive in nonteammode

Commit also adds info, if player1 wasn't spectator, to which team
he switched.
Fix gonext command and do it random

Commit fixes broken "gonext" command, reading time from maprot, and does
result of this command random.
It also removes get_next() function, because it messes up the maprot
and won't be already used.