Handle Selection and Transform

[mattlag]

Describe the new feature and what scenario it helps support:

When clicking on a blank area of canvas, start a drag / selection area. Show points and handles, and add points/handles within the area to multi-selection.

• Drag Select Area
• Toggle just points, or points+handles
• New concept of multi-select handles (possibly without it's point selected)
• Align point / handle actions
• Transform point / handle actions