Expose the 'Slide Show' plugin from the Macro Interpreter

The Macro Interpreter adds a command 'show' which does not work
otherwise.

Noticed by Jan Eglinger in bug 474.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Merge remote-tracking branch 'github/bug474'

Tested by Jan Eglinger. See http://fiji.sc/bugzilla/show_bug.cgi?id=474

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Build.sh: respect the -- option separator

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Build.sh: propagate the '-x' to other shell scripts

When called with 'sh -x Build.sh', let's also execute all shell
scripts called by Build.sh with the xtrace option.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Merge remote-tracking branch 'origin/master' into track-mate

Conflicts:
	Build.sh

Signed-off-by: Jean-Yves Tinevez <jean-yves.tinevez@pasteur.fr>