## Animation brush ups. Defined `AnimationAssets`.

###General:
New `AnimationAssets` and derived classes have been defined. Its purpose
is to provide some basic knowdlege about the sprite being animated for
the `SpriteAnimation`, e.g: sprite sheet width, height, texture region,
so the SpriteAnimation and derived classes can do basic manipulations
regarding the animation such as changing the "sub sheet" from the
original supplied texture region.

###`AnimationDirection`:
Animation type that has a direction.

###`AnimationAsset`:
New class for holding basic knowledge about the sprite sheet resource.

###`AnimationPersonAssets`:
Asset vault for the `Person` related animations.

###`AnimationPerson*`:
Concrete implemetnation of `Person` animations.

###`AnimationAssetInternalFile`:
An extenstion that allows to instantiate AnimationAsset from an libgdx
internal file.

###`SpriteSheet`:
`SpriteSheet` can now be instantiated from an `AnimationAsset`. Old constructors
will create a needed asset on the fly. The rest of functions use `asset`
field where appropriate.

###`Marker`:
The marker, does not set the animation for the objects on map but fires
up actions.

###`Person`:
`Person` does not hold current animation as some magic number but in a
`Animation currentAnimation` object. The actions that a `Person`
executes/performs such as `greet`, `attack` has been moved into the
`Person` class.

`Person` now uses "person asset vault" `AnimationPersonAssets` to create
animations.

Some code clean ups.