[WIP][CR]  Boats 

Add to game boats.

A while only inflatable boat (upd: *wooden* also available and can be crafted):

![excursion_3_inflatable_boat](https://cloud.githubusercontent.com/assets/6351438/3489118/f5901d24-0516-11e4-8aa2-95d226f22c8f.jpg)

You can fold/unfold it to carry in inventory and unpack near water. 

Engine - Paddles. It like pedals, but paddles.

Boats can swim by deep and shallow water. On the ground you can grab and drag the boat (or fold it to inventory).

You can fish from boat! Romantics!

![fish](https://cloud.githubusercontent.com/assets/6351438/3489136/2242b36c-0518-11e4-8970-1dcd376280f4.png)

"You painstakingly unfold, inflate, and launch the inflatable boat."  (presuming it only unfolds into water tiles)

Should probably need/come with a pump to inflate it?  I'm not inflating a raft like the one pictured by mouth, that'd take hours, if not days!