Improved the tests/run_on_mac.sh script
Improved the tests/run_on_mac.sh script

This script used to require edits for each individual system.  It now takes the path to the binary as an argument, avoiding the need to edit the script.

tests/run_on_mac.sh:
  - use cmdline argument to .app bundle
  - use PYTHONHOME instead of PYTHONPATH

hjanime/VisTrails,Nikea/VisTrails,minesense/VisTrails,hjanime/VisTrails,Nikea/VisTrails,celiafish/VisTrails,hjanime/VisTrails,VisTrails/VisTrails,VisTrails/VisTrails,Nikea/VisTrails,celiafish/VisTrails,minesense/VisTrails,minesense/VisTrails,Nikea/VisTrails,minesense/VisTrails,VisTrails/VisTrails,hjanime/VisTrails,minesense/VisTrails,VisTrails/VisTrails,hjanime/VisTrails,celiafish/VisTrails,VisTrails/VisTrails,celiafish/VisTrails