Replace fest-assert with assertj

fest-assert seems to have no activity.  Contributors seemed to have a
fallout.  Assertj appears to be replacement based off fest-assert
2.0-m10 base.  It is very active and mostly a simple change out.
fest-assert did a better job handling BufferedImage so a few new
utilities were necessary.  Also switched back some more standard junits
to not even use this type of assert.