Build mkgmap/splitter #188

remove costly test to reduce run time when using polygon(s) - remove a possibly costly test which never seems to return true with the current code. Not sure why I added this test in r429 and I wasn't able to debug r429 any more. The test avoids that the split contains a tile which lies completely outside the poygon, but such a split should be bad anyway. - throw SplitFailedException when bounding box of input file doesn't even intersect the bounding box of the polygon (caused a NullPointerException before)