BP_Document::array_msort( $array,  $cols )

	public static function array_msort( $array, $cols ) {

		$array = json_decode( json_encode( $array ), true );

		$colarr = array();
		foreach ( $cols as $col => $order ) {
			$colarr[ $col ] = array();
			foreach ( $array as $k => $row ) {
				$colarr[ $col ][ '_' . $k ] = strtolower( $row[ $col ] );
			}
		}
		$eval = 'array_multisort(';
		foreach ( $cols as $col => $order ) {
			$eval .= '$colarr[\'' . $col . '\'],' . $order . ',';
		}
		$eval = substr( $eval, 0, - 1 ) . ');';
		eval( $eval );
		$ret = array();
		foreach ( $colarr as $col => $arr ) {
			foreach ( $arr as $k => $v ) {
				$k = substr( $k, 1 );
				if ( ! isset( $ret[ $k ] ) ) {
					$ret[ $k ] = $array[ $k ];
				}
				$ret[ $k ][ $col ] = $array[ $k ][ $col ];
			}
		}

		if ( ! empty( $ret ) ) {
			$i   = 0;
			$arr = array();
			foreach ( $ret as $k => $v ) {
				$ret[ $i ] = (object) $v;
				$arr[ $i ] = (object) $v;
				$i ++;
			}
		}

		return $arr;

	}