Add class QgsComposerRuler
Add composer rulers to composer graphics view
Implement drawing of ruler markers
Fix ruler layout
Don't draw view frame (alignment with ruler widgets)
Fix calculation of ruler y-coordinates
Read composer from xml considers rulers
Better placement for y-coordinate labels
Show ruler marker for cursor position
Store reference to composition in ruler to get page info
Consider multiple pages for ruler scale
Improve coordinate display
Show snap lines in ruler mouse move event
Snap to arbitrary snap lines
Improve handling of snap lines
Implement moving of snapped features together with the snap line
Do not wait for feature form closing for non-editable layers
Refactor to avoid creating multiple QgsDistanceArea objects and recalculation of static or unused variables. Results in massive speed increase and fixes #6756, #6691 and #6692.
Automatically set the projection on output raster to match input layer
Separate units for line width, line offset, dash pattern