New commands: !paskuffle and !paminmoves

!paskuffle - skill shuffle, randomize fair teams
!paminmoves - balance teams by moving up to 30% of the players
clean up, also use xlrstats if available
Addition to changelog and versioning
really disable autobalance check while moving players
Merge branch 'master' of http://github.com/tomyl/b3-plugin-poweradminurt.git
!bbswap command and logging improvements from itsme at bubbleclub.de
make sure we don't cause a "too many players in team" error while moving players
Skill shuffle algorithm tweaks

We now damp the score for newly joined players. The score now
also includes headshot statistics. Both !sk and !min will also
try to distribute the snipers between the teams.
Merge branch 'master' of http://github.com/tomyl/b3-plugin-poweradminurt.git

Conflicts:
	extplugins/poweradminurt.py
inserted an try ... except construct on getting g_allowvotes to avoid an exception on empty cvar
misc !sk + !min fixes

 * the balancer didn't pick the best balanced teams while distributing the snipers
 * the player who initiates !skuffle won't switch team anymore
 * fixed bug in _move(), it didn't always start by moving players to the smaller team
 * refactoring, !sk+!min now use the same function for finding new teams
custom config by mode. add setwave and setgravity commands
fix getScores when xlrstats plugin is not available
Merge pull request #7 from dahool/master

New commands. One major fix. Some minor enhacements
!paswap now uses _move helper function
sniper splitting improvement

 * ignore noobs with sniper rifles
 * consider psg1 also as sniper rifle
balance teams by number first, then by skill
experimental change to the team skill balancer

The skill balancer now normalizes the player scores using the most skilled
player's score. Also, all terms in the balancing formula are now weighted
(hard-coded for now, this should be moved to config later).
Auto skill balancer

Can automatically skill balance teams or provide suggestions, both based on
threshold values.

We need a way to automatically trigger the skill balancer based on when players
might perceive the game as unfairly balanced.

To do this we calculate team contribution (player's worth to team as
kill-deaths) and take this averaged for the top players in each team (because
the top players affect how the game is perceived by the opposing team).

The difference in this avg values between the two teams determines how the game
is progressing (specifically how much a team is dominating TDM). This is
DATCPM - Difference in Average Team Contribution Per Minute.

We provide 4 modes of operation:

1) Do nothing :-)
2) Suggest - team strength is shown, with a suggestion to shuffle if
   DATCPM is higher than threshold.
3) Auto-min - team strength is shown, perform minmove for same reason
4) Auto-skuffle - team strength is shown, perform skuffle for same reason

The threshold is anecdotal and can be tweaked in the settings, though this will
leave eminent Swedish scientisticians unhappy :P

A new command !paautoskuffle (!ask) makes it possible to switch between the
modes in-game.

TODO:
 - rename !pabalance (!bal) to !pacheckbalance (!chk)
 - rename !paminmoves (!min) to !pabalance (!bal)
minor change for 1.7 and method fix