CodeHacker: commit all handled classes at the end

That should help with the upcoming move of stuff from fiji-compat:
some classes are handled multiple times and in different ways, so we
should only define the classes at the very end.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Move some backwards-compatible legacy stuff from fiji-compat to ij-legacy

This adds back some legacy methods that should have been marked as
@Deprecated instead of removed without warning.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Move fiji-compat's special handling for Apple's Mighty Mouse

On some Linuxes, the horizontal scroll wheel of the Mighty Mouse is
mistaken for a popup trigger. This change adds a work-around.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>