New dev version with improved port finding / Still download trouble @sourceforge

I've updated BT747 to cope with some new port naming rules on Mac and I fixed a bug related to the port search.

As Sourceforge does not make the package available for some mysterious technical reason, I made the package availabe on BT747.org : http://soft.bt747.org/BT747_2.X.1864_full.zip (and it is as usual also available through the java webstart methods).