Build 7248

I just uploaded another build to http://www.grzsoftware.com/files/MeshCAM-Setup.exe .  It contains only one fix- Joe S. helped provide me with a file that demonstrated the rare "horizontal edge gouging problem" that has been lurking for a while.  I was able to reduce the file to only two triangles that demonstrated the problem and find the bug.  It was in an area deep within MeshCAM so I tried to limit the changes to the minimum required to make the problem go away.  As it stands I believe the problem is gone but I may go back and reengineer some of this code for V3 to make it more robust.