Remove superfluous ImageJ plugin

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

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

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Tell Maven's exec:java to execute our main class by default

It is quite convenient to be able to tell Maven to execute the plugin
(thanks to the main() method) by calling

	mvn package exec:java

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

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