linepot constuct name same as their class will not be constructors in a future version of PHP

```Methods with the same name as their class will not be constructors in a future version of PHP;
 LinePlot has a deprecated constructor
jpgraph/jpgraph/lib/jpgraph/src/jpgraph_line.php',\n  'line' => 24
```

construct function name same name as their class will not be constructors in a future version of PHP.
I　use php version 7.1, It's will raise a 8192 type  exception
