uv3 jcasgen from Eclipse plugin, limited, fails on some levels of Eclipse

A user reported on Mars / Linux, running JCasGen with limited from the gui failed to do anything (nothing was generated, no error messages).  Traced this to the eclipse getProject().getLocationURI().getPath() returning a path which started with "/default/".  This is unexpected, what was expected was the full path in the file system. 

Fix by using getProject().getLocation().toString().