jme3-core: correct more typos in comments

jme3-core/src/main/java/com/jme3/cinematic/events/MotionEvent.java

@@ -363,7 +363,7 @@ public class MotionEvent extends AbstractCinematicEvent implements Control, JmeC
     /**
      * Sets the direction of the spatial, using the Y axis as the up vector.
      * Use MotionEvent#setDirection((Vector3f direction,Vector3f upVector) if 
-     * you want a custum up vector.
+     * you want a custom up vector.
      * This method is used by the motion path.
      * @param direction
      */

jme3-core/src/main/java/com/jme3/post/FilterPostProcessor.java

@@ -590,10 +590,10 @@ public class FilterPostProcessor implements SceneProcessor, Savable {
     }
     
     /**
-     * returns the first filter in the list assignable form the given type 
+     * returns the first filter in the list assignable from the given type 
      * @param <T> 
      * @param filterType the filter type
-     * @return a filter assignable form the given type 
+     * @return a filter assignable from the given type 
      */
     @SuppressWarnings("unchecked")
     public <T extends Filter> T getFilter(Class<T> filterType) {

jme3-core/src/main/java/com/jme3/shadow/PssmShadowUtil.java

@@ -75,7 +75,7 @@ public final class PssmShadowUtil {
     }
 
     /**
-     * Compute the Zfar in the model vieuw to adjust the Zfar distance for the splits calculation
+     * Compute the Zfar in the model view to adjust the Zfar distance for the splits calculation
      */
     public static float computeZFar(GeometryList occ, GeometryList recv, Camera cam) {
         Matrix4f mat = cam.getViewMatrix();