ejeschke/ginga: Ginga v6.0.0

Whats New Added ability to add icons to Ginga-wrapped Button widgets Refactored Pan and Header plugins to use new parent/child plugin implementation Fixed an issue with setting filters in Gtk based FileDialogs Refactoring of the Control module of the reference viewer to separate viewer logic from the workspace and plugin management You can now set the start attribute for a local plugin in the plugin spec and it will start when a new channel is created New ability to have more than one instance of a global plugin (if enabled) and more than one instance of a local plugin per channel (if enabled) local plugins with this enabled: Pick, Cuts, Histogram, Ruler, Drawing, PlotTable. Check use of "ident" attribute in the plugin code and setting singeton=False in the plugin spec Added a background to Crosshair text for better readability Refactored cursor readout to allow for more flexible ways to override the default. You can now register a function to the 'pixel-info' callback on a canvas, and return the information to show in the readout. Fixed an issue where there was an unintended fill in drawing a Bezier curve with the Qt backend Improvements to plugins to use the new the plot viewer (event callback API is changed, thus bump to new major version), but should be backward compatible aside from event callbacks Fix to handling of pan/scroll with touchpads in Qt6