nl_tokens: Create css build function
pl_tokens: function css ( files , output , options ) { options = Object . assign ( { banner : false } , options ) ; return ( ) => { var build = gulp . src ( files ) if ( options . banner ) build = build . <mask> ( $ . header ( banner , { pkg } ) ) ; build = build . pipe ( $ . rename ( 'd3.compose.css' ) ) . pipe ( gulp . dest ( output ) ) ; return build ; } ; }