Try to import our tile grapfics

[LinuxDonald]

Try to import our tile graphics that mapper could create an development map.

https://github.com/unknown-horizons/unknown-horizons/tree/master/content/gfx/base/moderate

[yigitozdemir]

I am adding a new pull request for this.

edit: #39 created for this issue.

2nd edit: I think importing existing assets is very important to create a structure and general testing environment as fast as possible. After importing those images i can work on importing more images and sounds to game.

[YeldhamDev]

Those are already in with a top-view rendering, as the world is now 3D with a faux-2D style, those are no longer needed.