I’ve finally merged the Qt5 codebase in the to34 branch into the master and tested it with Qt5 and it compiles and runs.
If you are compiling under Linux (i.e. Ubuntu) using Qt5 (or other OSs for that matter), you should be able to compile and run successfully now.
This is a really great project, and you sir are to be commended for releasing it into the public domain. I have a feature suggestion which I think would make setting up a workpiece a lot easier, and that is keyboard shortcuts. The most useful shortcuts would be jog keys, together with other keys to change the step size. One could use the LinuxCNC shortcuts (http://wiki.linuxcnc.org/cgi-bin/wiki.pl) as a starting point.