new functions linearmode

New functions:
- ability to wait with changing the pointlimit until the round ended
(actualy it will wait until beginround)
- command (/admin linearmode) with a window to change settings
(offset,multiplier,min+max pointlimit, wait for next round and a switch
to turn the linearmode on and off).
- Fixed/changed small things
Merge pull request #6 from tomvlk/master

new functions linearmode