Update to experimental r13565
Update to experimental r13543
More header cleanup
Minor pass of header cleanup
DrawingContext: change variable names ct to dc (bug #1272073)
make grayscale viewmode color factors configurable.
Cleaned up display-forward.h, including many redundant usages.
Next pass of doxygen @brief cleanup.
Add user preference for rendering cache size
More generic handling of child type in DrawingItem. Fix clip object selection bug (LP #365458).
Initial autocache work
Rewrite NRArena -> Inkscape::Drawing. Call render and update methods on the Drawing rather than on the root DrawingItem.