Panning with space key (#579)

* Panning with space key

* prevent panning when selecting/dragging & add more checks

* Fix changing current tool via shortcut while panning

* Fix order of statements

* teardown on blur event

* Refactor cursor setting

Co-authored-by: David Luzar <luzar.david@gmail.com>

src/keys.ts

@@ -13,6 +13,7 @@ export const KEYS = {
       : "ctrlKey";
   },
   TAB: "Tab",
+  SPACE: " ",
 };
 
 export function isArrowKey(keyCode: string) {