FirstPersonControls: Damping, separate move sources, release fix, E/Q keys. (#2239)

Author: Methuselah96

types/three/examples/jsm/controls/FirstPersonControls.d.ts

@@ -14,6 +14,15 @@ declare class FirstPersonControls extends Controls<{}> {
      */
     lookSpeed: number;
 
+    /**
+     * How quickly the movement and look velocity catches up to the input. Lower
+     * values feel heavier (more inertia), `1` disables damping.
+     *
+     * @type {number}
+     * @default 0.1
+     */
+    dampingFactor: number;
+
     /**
      * Whether or not it's possible to vertically look around. Default is `true`.
      */