HID: Refactor MS Presenter 8K key mapping

Following the suggestion of Jonas, this patch maps the special keys of
the MS Presenter 8000 to targets that should allow for better re-mapping
according to individual use cases (i.e. I avoided hard-wiring to
standard keys). This time I also included the last missing key event
(switching back from presentation mode).

The optimal Xmodmap customization for using the Presenter with
OpenOffice now looks like this for me:

keycode 175 = Escape
keycode 179 = F5
keysym XF86Forward = Right
keysym XF86Back = Left

Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>