Missing GetHashCode method.
Implemented OAM class.
Renamed OAM to Obj and finished its implementation

OAM (Object Attribute Memory) is the place in the RAM
where the Objects are. Objects are moveable sprites.
More info at GBATEK.
Factory method to create Objects
Frame implementation
Implemented CreateBitmap of Object
Implemented Subimage creation.
Implemented a basic Sprite structure
Implemented sprite NCER file format (only read).
Fixed minor bugs in LABL and NCER formats.

Labl: Block size includes the "header".
Ncer: Tilesize is the result of 2^(5 + value) where the value
is only the first byte. The other data is unknown.
               Added properties with the unknown values to debug.
Added a warning to check if the number of blocks is invalid.

Found several damage NCER files with that. Now it doesn't 
make an exception. It seems the developpers really don't care
to follow the standard (hey!, copy the 3 of num blocks but do not generate
the LABL block) -.-'
Added original variable and fixed bugs creating subimages.

By using original data variable it will save time encoding again the
decoded data.
Since the new subimage will have different size, its data must be
decoded using the new size, for this reason it needs to use the
original, undecoded, data.
Fixed bugs with the ROI of sprite images

* Ncer.cs: Fixed problem reading rectangle area (signed values)

* Frame.cs: Fixed problem with the Frame ROI (Offset negative
  coordinates)

* Tests.cs: Added test to extract sprite images.
Implemented GetTile using original data var.

It's more intuitive and faster.
Improved test to extract all sprites frames
Fixed bug of obj priority creating the sprite image.
Implemented transparency in Objects.

* EmguImageExtension.cs: Faster SetPixels and implemented overlay
  method.
Since the array are class and the Data property does not return
a copy but the internal variable, there is no need to set it again
  (slow).

* Frame.cs: Implemented transparency in Objects.
Fixed TileNumber to Pixel index conversion and transparent color

* EmguImageExtension.cs: Fixed bug setting transparent color visible
  when layer and image have alpha channel set to 0.

* Frame.cs: Added tileSize variable to generate correctly the object
  bitmap. Needed for tile number to pixel index conversion.
Fixed bug with transparent color (temp until Emgu.CV is fixed)
Disabled frame ROI until further research is done.

* Obj.cs, Image.cs, Ncer.cs: Fixed tilenumber to pixel index
  conversion (using tilesize from NCER file)
Fixed negative X coord, tile index for 8bpp images and vertical
and horizontal flip.

X Coordinate is in two's complement 9-bit format.
Fixed bug when horizontal and vertical flags is set at the same time.
For 8bpp images, we don't need to multiply the tile number by two.
  This  is neede for 4bpp since the NDS works with tiles of 2 px / 1 byte
  and the internal data array in images with 1 px / 1 entry.
Basic template of sprite importer