*) added new filter 'FILTER_INVERT' and new method ymageMatrix.invert() to use it (does not work where characters have been written with ymageToolPrint.print(), haven't found the reason yet)
*) fixed a possible arrayOutOfBoundsExceptions in filter() if y-value of area to use filter in was larger than height of image filter is used with
git-svn-id: https://svn.berlios.de/svnroot/repos/yacy/trunk@4279 6c8d7289-2bf4-0310-a012-ef5d649a1542