CHG: all @marshmellow42 's changes to make the reveng work.

CHG: all @marshmellow42 's changes to make the reveng work.
ADD: lua script test for using the reveng inside lua.  *prove of concept*
      it implements -h help
                    -d  data in a hexstring
                    -w  width of the crc family. (ie 16 gives all CRC-16 calculations.
     it iterates thru all found crc presets in a crc family based on the width of crc.  It calcs crc and the reverse crc.