BUG: In the second patch in 2edf328 it was wrongly assumed that rescale slope always had a valid value, however we need to check that rescaling is used before using the value of rescale slope. This change avoids using a float scalar type when rescale is not defined, fixing two issues:
1. Float was used in cases where a smaller integer type could be used, therefore wasting memory.
2. DicomImage with a float internal type can't be rendered, and therefore thumbnails can't be created when float is chosen. This change avoids using float when it's not needed, which is most cases, so most thumbnails can be created. However in case of a single frame image with a rescale in the range (-1, 1), float will still be chosen and thumbnails will fail. This problem shall be fixed in the future.
BUG: Revert "﻿ENH: DX and RF hanging protocols are no longer needed". This reverts commit 4c8d1c26e615ab195d6e76987b4270bcccba6423 and fixes ticket #2094.