initial ground work
more groundwork
#21: fixes
metomi/rose#21: more undo grouping
much faster undo/redo
metomi/rose#21: more groundwork
subclassing
metomi/rose#21: fix grouping
metomi/rose#21: progress with custom interface
metomi/rose#21: add/remove functionality
metomi/rose#21: more work
metomi/rose#21: further improvements
metomi/rose#21: more fixes
metomi/rose#21: better handling of alphanumeric indices
metomi/rose#21: speed up add, copy, remove sections
metomi/rose#21: fix comment bugs
metomi/rose#21: bug fixes
metomi/rose#21: update
metomi/rose#21: better subclass documentation
metomi/rose#21: fix add section