"Rotate Clockwise" and "Rotate Counterclockwise" actions now work in Things...

"Rotate Clockwise" and "Rotate Counterclockwise" actions now work in Things mode (they will rotate things) and in Sectors mode (they will rotate floor/ceiling textures based on current view mode).
Moved "Rotate Clockwise" and "Rotate Counterclockwise" actions to "Edit" category.
Tag Statistics form: help label was incorrectly aligned.
Some actions in Sectors and Linedefs modes were not used on highlighted map elements.
Some actions in Sectors and Linedefs modes created undo groups incorrectly when used on highlighted map elements.