#1 Write some documentation

[Gabriel Galibourg]

- How to start the application
- How to use the interface, ie:
+ zoom (ctrl+, ctrl-, or ctrl+left mouse button)
+ move (shift+left mouse button)
+ waypoint: ctrl+middle mouse button
+ menu: right mouse button

- where to get GRIB files from, w/ examples
- how to navigate a GRIB file

For developpers:
- how to localise the application