Draw full circle pie slice (100%) as a primitive

Allows getPieSlicePath to draw a full circle pie slice (100%) by slightly adjusting endpoint to have a valid arc. Also hides a central line as there will be no more pie slices.
Remove 100% pie slice hack

The getPieSlicePath primitive can draw it now.
Do not hide OK hosts and services from the Pie Chart

Having a single hostgroup, and all hosts and services up, landing page Pie Chart is empty. This restores display of OK hosts and services.
Fix coding style