ArgWriter will write a tile to disk in ARG format.
Each instance of ArgWriter is provided a data type (e.g. int or float) to
use for output files.
Write a tile in ARG format to the specified path.
The outputFilePath argument should be the full file path (including file name and extension)
to which the tile file should be written. For example, "/var/data/geotrellis/mytile.arg".
The metadataName argument is a logical name for the tile that will be included in the tile's
metadata. It does not have to match the output filename. This filename is used by the catalog
when a tile is loaded by name as opposed to filepath.