fixed a small nasty bug, that occours in the DropCutter for small values of "material allowance"
 
 Description: ODE did not take the "extended" drill shapes into account, when deciding, if
 collisions are possible. Thus the collide callback was never called.


git-svn-id: https://pycam.svn.sourceforge.net/svnroot/pycam/trunk@155 bbaffbd6-741e-11dd-a85d-61de82d9cad9