add convert_type coercion modelled after rb_convert_type
add convert_type coercion modelled after rb_convert_type

babelsberg/babelsberg-r,babelsberg/babelsberg-r,topazproject/topaz,kachick/topaz,kachick/topaz,babelsberg/babelsberg-r,topazproject/topaz,topazproject/topaz,kachick/topaz,babelsberg/babelsberg-r,babelsberg/babelsberg-r,topazproject/topaz