Improvement - path overlay

```
Hi,

I implemented a path overlay, for drawing GPS traces.

Made some modifications in OpenStreetMapViewProjection, to get better
performance on large traces.


```

Original issue reported on code.google.com by `viesturz` on 7 Apr 2010 at 11:50

Attachments:
- [path-overlay.patch](https://storage.googleapis.com/google-code-attachments/osmdroid/issue-36/comment-0/path-overlay.patch)
