Converted QTFormat

Converted the LegacyQTReader/Writer and NativeQTReader/Writer from
loci.formats to LegacyQTFormat and NativeQTFormat, respectively, in
ome.scifio.formats.

Created a QTFormat that parallels QTReader, similarly.

Removed DelegateReader class from loci.formats in favor of a new
DelegateFormat class instead, to facilitate this conversion. The
DelegateFormat interface covers the scenario when multiple formats
support the same image type. Toggling between legacy/native is done
through the delegate format, and simply determines which components are
created.
Converted NRRDFormat

Converted the loci.formats NRRDReader to an ome.scifio NRRDFormat.
Converted PICTFormat

Converted the loci.formats PictReader to an ome.scifio PICTFormat.