Node

• [Canvas] Add ability to add, subtract selecting area by holding Shift, Alt key.
• [Canvas] Outline tools can now be applied to the selection mask by holding the shift.
• [Canvas] New node tools allowing nodes to be loaded and rendered on the selecting area.
• [Canvas] New mirror tools. Mirror the current brush stroke by the center of the canvas/selection.
• [Canvas] New brush tool converting current selection to a brush.
• [Canvas] New curve tool.

Bugs

• [Canvas] Fix background drawing mode with selection creates results with the wrong color.