Fixed a bug in JPWL module, which prevented to exploit the full error correction...

Fixed a bug in JPWL module, which prevented to exploit the full error correction capability of RS codes (e.g. it gave up at 5 errors, even if 6 were correctable); defined a JPWL_MAXIMUM_EPB_ROOM for better customization of the maximum dimension of EPBs (the dimension is pre-calculated on an hypothesis, if it goes beyond 65535 there will be problems, thus we give a little less than the max, let's say 65450)