Continuing the discussion from SketchUp 2016 Wish list:
Select the Component and then hover the Move tool over the selection.
Notice the compass rose that appears and the four grips within it.
Click on one of the grips to begin the rotate operation.
The rotation snaps incrementally if the cursor is held close to the rose.
Moving the cursor further away from the rose allows the selection to rotate freely.
Click to finish.
One can also specify a certain amount of rotation via the keyboard.