Log Message:
- Update to 1.18
- Grab maintainership
- Update homepage
- Make pkglint happy
- Highlights include:
	Add better check that GD is really installed
	Guide lines for pie plots
	Add Cleanup() method to delete all allocated objects within the graph.
	Add new date scale for X-axis
	Add Interlaced PNG feature
- See the following for more details:
	http://www.aditus.nu/jpgraph/changes.php?v=5
	http://www.aditus.nu/jpgraph/changes.php?v=7