Fix for #441, #440, #439, #438 (Mirror/GeomUtil)

[80prozent]

I made some changes to the "tools/command/mirror.as" and the "tools/utils/GeomUtil.as" to eliminate the bugs reported in issues #440, #439, #438.

This is my first Commit to another Repo than my own, so i hope i am doing this the right way.

[80prozent]

I addet a optional parameter "addionalOffset" to the apply() function of Mirror.as.
I dont think it adds much to the calculation-time, but is quite usefull.

[80prozent]

Fabrice had the idea for the functions in my last commit.
To test this functions, try this code:

var wheel_FrontLeft:Mesh;
var wheel_FrontRight:Mesh;
var wheel_BackLeft:Mesh;
var wheel_BackRight:Mesh;

wheel_FrontLeft = new Mesh(new CylinderGeometry(30, 30, 20,16,1,true,true,true,false))
wheel_FrontRight = mirror.getMirroredClone(wheel_FrontLeft, Mirror.Z_AXIS, Mirror.CENTER, 0);
wheel_FrontLeft.z = -120;
wheel_FrontRight.z = 120;
wheel_FrontLeft.x = -160;
wheel_FrontRight.x = -160;
wheel_BackLeft = mirror.getMirroredClone(wheel_FrontLeft, Mirror.X_AXIS, Mirror.CENTER,0);
wheel_BackRight = mirror.getMirroredClone(wheel_FrontRight, Mirror.X_AXIS, Mirror.CENTER, 0);
wheel_BackLeft.x = 160;
wheel_BackRight.x = 160;

wheel_BackLeft.material= new ColorMaterial(0x00AA33);
wheel_BackRight.material= new ColorMaterial(0x00AA33);

wheel_BackRight.rotationZ = 10;
wheel_BackLeft.rotationZ = 25;
wheel_FrontRight.rotationZ = 35;
wheel_FrontLeft.rotationZ = 75;

scene.addChild(wheel_FrontLeft);
scene.addChild(wheel_FrontRight);
scene.addChild(wheel_BackLeft);
scene.addChild(wheel_BackRight);

[Fabrice3D]

done