function moveRange(range, numLines) {
        return {from: CodeMirror.Pos(range.from.line + numLines, range.from.ch),
                to: CodeMirror.Pos(range.to.line + numLines, range.to.ch)};
    }
Helper function to move a fold range object by the specified number of lines
@param {Object} range    An object specifying the fold range to move. It contains {from, to} which are CodeMirror.Pos objects.
@param {Number} numLines A positive or negative number representing the numbe of lines to move the range by