Routing now avoiding land

Sounds obvious, I know, but the routing is now - on request - able to avoid land.

The feature is being developed - ie it works on my machine - and will be available in beta soon (in 3.0.0.5).
There will be some limitations for the inland seas, like Caspian, Aral, Black Sea, Great Lakes... But that should beOK for the rest of us.
As always, the code will be available on Google Code.