Enhancements to the ipg HTML notebook widget
Enhancements to the ipg HTML notebook widget

- refactored the way the GUI is built so that custom viewers can be
  more easily constructed

pllim/ginga,pllim/ginga,pllim/ginga,ejeschke/ginga,naojsoft/ginga,ejeschke/ginga,naojsoft/ginga,ejeschke/ginga,naojsoft/ginga