Integrate the nl-BE-translation.ctb module into nl-BE-g1.ctb

do the same for nl-NL-g0-translation.ctb and nl-NL-g0.ctb
Rename nl-NL-g0 to nl-NL-g1

in order to be consistent (Belgian table is also g1)
Delete old nl-be-g1.utb and Nl-Nl-g1.utb tables
Add Henri Apperloo to AUTHORS and update copyright notice