Fix Eyesis_Correction and JP46_Reader_camera

Plugins must not extend or instantiate frames in order to be run in headless mode,
they must implement "PlugIn" and the entry point should be method run(); AFIK

- Eyesis_Correction can now be run from macro:
  run("Eyesis Correction","prefs=<path_to_xml>");

- or in headless mode from Fidji command line:
  ImageJ-linux64 --headless --run Eyesis_Correction prefs=<path_to_xml> ...
fix JP46_Reader_camera showGui