GFX update, round #1

[Laurent Chea <contact@xxxxxxxxxxxxxxx>]

Hello world.

Here are the first results of the gfx updates I've done today.
The map is by myself, called GFXupdate.

What to notice :

- more bump in water without being too shiny
- bridges (including roads and rails) drop shadow on water
- buildings have more details (it mays however make some maps 
"uncompatible" (some weird results)
- broken roads have more details
- beaches are more "fading" in with the default grass tile

What i'm working on now :

I'm currently working on those famous mountains :)

What I'm wondering about :

Making the units to drop shadow, but it may be confusing, i'll try.

Any comment or suggestion will be appreciated :)