[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)

This mesage just mean, that boat is on the land and can't swim.

Anchor may be useful if the rivers in game having flow, but no flow in game. May be make so: boats several times moves randomly?