ImgUtilityService: moved decodeWord method

The decodeWord method used by the RandomAccessConverter is now located
in the ImgUtilityService. This will allow for standard conversion in any
converter method that requires it.
Array loaders: add type conversion if needed

All array loaders were assuming that the provided byte array was in
their native type.

From now on they will check compatibility between input and output data
types, and convert using the classic decodeWord logic and casting from
a double.

Closes #93
Tools: use project.version

Updated the SCIFIOTools to always use the current project version, to
prevent them from lagging behind with old versions.