Add basic tile representations

Tiles (sprites) are now available. They can be loaded via the
TilePackage constructor.
Note that tiles and blocks are not the same.
Add blocks

This includes not only blocks, but also a way to implement blocks (the
generic block) and a „block director“, a class associating integers
with blocks. The world can get the block ID of any game coordinate and
get the associated block from the block director. Using this technique,
there are only as many blocks in memory as there are kinds of blocks
and not as many as there are in the world.
Add chunks.

Chunks are little extracts of the game world, each containing a limited
amount of blocks. With this technique, not the whole world has to be
loaded into memory, but just little chunks of it.
Add equals and hashCode functions to most classes.

These classes are:
- BlockDirector (also add documentation for getBlock method)
- GenericBlock
- GameCoordinate
- ImageExtract
- MonitorExtract
- TilePackage
- World
Add test class for Chunk

This also includes adding the junit dependency to the pom.xml file.
Add wizzard-idle image.

This image is displaying a 32px * 32px standing idle wizzard, looking to the right.
Add more blocks (grass, earth, iron, stone, copper)
Add texture to wizzard-idle.png
Add even more texture to wizzard-idle.png
Add javadoc plugin to maven pom.xml
Change chunk mechanics and add first printable versions of class "World", as well as smaller improvements.

This commit includes changes to some more basic mechanics like ImageExctract and MonitorExtract, as well as a seperate ChunkCoordinate class and Entities and Players (whereas only the Player is included in the game world yet).
Merge branch 'resources' into tile-mechanics
Implement drawing

The World class is now able to draw itself. Furthermore, this commit includes:
- more documentation
- Entities now have tile IDs
- the player can move via the arrow keys (actually not completed)
- bugfixes
Add first executable version of the game (more like a test)
Merge branch 'tile-mechanics'