BUG: Fix alpha assignment for RGBA TIFF.

The alpha value should not be inverted.

Add additional test file baseline for regression testing.

Co-authored-by: Мар'ян Климов <nekto1989@gmail.com>
Co-authored-by: Ivan Kubarev <Ivan.Kubarev@materialise.kiev.ua>

Change-Id: Ic865abb18fe11739df0633888423a4b302efc2ec
BUG: Improve thread-safety and performance of PCAShapeSignedDistanceFunction.

m_Selectors is a smart pointer, and if manipulated by multiple threads, there
can be race conditions to set its value.  Through some refactoring, this
member variable is no longer needed and is removed.

Change-Id: I762dd7751e7ebfab39f77f11b1cd3ab653c69c04
Merge branch 'PCAShapeSignedDistanceFunction_release' into release

Change-Id: I4c587711aa5fa21157fa2d70b419dbcd74cbd16d
BUG: TransformFileReader does not clear its TransformList.

Calling multiple times will generate the wrong results.

Change-Id: I3f8e01ea18393968c9327f16a847de321729c9a7
BUG: Prevent dangling pointer in HDF5TransformIO.

If Read() or Write() is called multiple times, and an exception occurs during

  this->m_H5File = new H5::H5File(this->GetFileName(),H5F_ACC_TRUNC);

on the next round delete this->m_H5File may be a dangling pointer, and

  delete this->m_H5File;

is dangerous.

Suggested-by: András Lassó <lasso@cs.queensu.ca>

Change-Id: I7a601c71358b8bfcf6388bbb6f30954054b2df09
Merge branch 'RGBATiff' into release

Change-Id: Ie9b2684e934b0c9466b888e582917bbf78c8ae96
BUG: Use METER of sCAL scale unit

Change the scale unit field in the image to be PNG_SCALE_METER. The
image previously have a UNKNOWN unit type, which roduces a
warning in libpng 1.5, and the actual scale is ignored. This resulted
in the SignedMaurerDistanceMapImageFilterTest3 failure due to
different image spacings.

Change-Id: I3340f36fe1ce44308993f1720fc1fd2e66b88a2e
BUG: Use PNG_SCALE_METER for PNG sCAL unit

With libpng 1.5 if the unit is UNKNOWN when reading then an error is
printed, and the other spacing values are ignored. By writing METER
unit, the resulting png can be correctly read with spacing.

No unit conversion is done to preserve compatibility.

Change-Id: I74f4240221d31edecf2248425167659857326009