javadoc: link to Pivot's API documentation
javadoc: link to Pivot's API documentation

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

This used to be revision r4984.

biovoxxel/imagej,biovoxxel/imagej,TehSAUCE/imagej,TehSAUCE/imagej,biovoxxel/imagej,TehSAUCE/imagej