BUG: Assert unchanged pixels only for non-PALETTE_COLOR images

Change-Id: I1781cf8cdcaf26a54311bf1bd7e2338230465e70
BUG: Add test case for GDCMImageIO

Change-Id: Ifd9bdc15145d47e0c2a2edd6d43e454152296f33
BUG: Preserve backwards compatibility with types

The decoupling of types for float and double presision
did not preserve backwards compatibility when only 3
template arguments were given.

Change-Id: I1d5c334bf74cac72693b29e0492f83032bb875d6
ENH: fix std::string usage
Merge topic 'FixBackwardsCompatibilityInCornerCase'

3a47ad4 BUG: Preserve backwards compatibility with types
Merge topic 'GDCMImageIO-without-assert-on-PALETTE_COLOR'

26930bc BUG: Add test case for GDCMImageIO
178d712 BUG: Assert unchanged pixels only for non-PALETTE_COLOR images