Add support for INI files representing a Metaxpress plate

[melissalinkert]

Be sure to check the Channel.EmissionWavelength, Pixels.PhysicalSizeX, Pixels.PhysicalSizeY, and Plane.ExposureTime values in the generated OME-XML. The logic there is slightly different, as it uses an OMEXMLMetadata to transport values instead of getters on MetamorphReader, as getters for those four values are not present in current Bio-Formats.

[mabruce]

Channel.EmissionWavelength, Pixels.PhysicalSizeX, Pixels.PhysicalSizeY, and Plane.ExposureTime are all present in the OME-XML. Conversion of a plate from the INI format to OME-NGFF works as expected.