Snap everything to grid (#315)

* Implement snap to grid

- Moves positioning logic to LGraph
- Simplifies code
- Adds Pointer API to alt-clone node
- Removes always_round_positions, replaced by always snap to grid (default size is 1 when always snapping)

Fix refator error

* Fix group items snapped without group

* Allow snapping of all items

- Add snapToGrid to Positionable
- Impl. on all types
- Deprecated: alignToGrid is now a wrapper

* Fix test import alias, update expectations

* Prevent desync of before / after change events

Adds ability to perform late binding of finally() during drag start.

* nit - Refactor

* Fix unwanted snap on node/group add

* nit - Doc

* Add shift key state tracking for snap to grid

Private impl., no state API as yet.

* Add snap guides rendering

Nodes, reroutes

* Optimisation - reroute rendering

 Fixes exponential redraw

* Add snap guidelines for groups

src/types/globalEnums.ts

@@ -6,13 +6,19 @@ export enum NodeSlotType {
 
 /** Shape that an object will render as - used by nodes and slots */
 export enum RenderShape {
+    /** Rectangle with square corners */
     BOX = 1,
+    /** Rounded rectangle */
     ROUND = 2,
+    /** Circle is circle */
     CIRCLE = 3,
+    /** Two rounded corners: top left & bottom right */
     CARD = 4,
+    /** Slot shape: Arrow */
     ARROW = 5,
-    /** intended for slot arrays */
+    /** Slot shape: Grid */
     GRID = 6,
+    /** Slot shape: Hollow circle  */
     HollowCircle = 7,
 }