SDTFormat: make sure pixels are returned properly

If the SDTReader can't do a direct read, it will create a new byte
array, which then was not being attached to the returned plane.

Fixed by always updating the plane's data object.
SDTInfo: account for both channel keys

Previously only "SDT_SCAN_RX" was being accounted for, but there is a
"SDT_SCAN_RY" key that appears as well.

Both of these keys are now checked during metadata parsing and their
values are summed to find the total number of channels in the dataset.
SDTFormat: update to latest version

The initial SDTFormat was based off an older Bio-Formats version.
Updated to remove some hacks and unnecessary code.
SDTInfo: add ReadBlockHeader method

Added a convenience method for reading block headers. There are
situations (e.g. to support Csarseven data) where there are many headers
per file, so it is necessary to isolate this logic for reuse.
SDTInfo: apply style template

Updating style to the SCIFIO template.
SDTFormat: add Csarseven support

Copied a hack from Paul Barber to support Csarseven (old style) SDT
image files.

These files have one data block per pixel. If any non-csarseven SDT
formats also have more than one data block, we may need to update this
hack.