PERF: Improve recursive Gaussian perfromance with VectorImages

The VariableLengthVectors were causing multiple per-pixel memory
allocations. This arithmetic was refactored into a function where it
is specialized for the VariableLengthVector.

Change-Id: If33c9ba4df9ac5c84bbcc553f4087df1ec4ac1cf
BUG: ExtractImageFilter::CollapseToSubMatrix fix

When copying directions from an image of higher dimension the index used
to access directions was the one of the lower dimension image.

Change-Id: I87e900ef7eee81e592c3c8ac68c92243afae09ea
ENH: Query libtiff to determine compression support

Depending on the version of tiff used and how it is configured will
yield support for different compression codecs. The libtiff method
TIFFIsCODECConfigured is now queried to determine support.

If the compression is not supported than both the scanline and the
RGBAImage read methods will fail. The codec is now checked and if it's
not supported than a better exception is thrown.

The TIFF Compression RGB baselines image have been corrected from RGBA
images to RGB image.

Change-Id: I493cbb9d602f7902ced0c92f664c69238bf4bb52
BUG: Support TIFF tiled image with TIFFReadRGBAImage

Disable trying to read tiled tiff images with ITK native code instead
relay on the libtiff rgba library method.

Change-Id: I4fca0d0ffb6c82e7239502515668f29d67ff5710
DOC: More chapter 2 edits

Change-Id: I60c0ac9da5d53a61faba565016778edb782bca4e
ENH: Add a test on extracted directions in CollapseToSubMatrix mode

Change-Id: I80e8c0405411a5a2b7efb89988b9e9bb0aaa8550
COMP: Valgrind detects uninitialized memory read

The intensity values are not used, but they need
to be initialized to avoid valgrind warnings.

Change-Id: Idd468d699e78176c0860b2ac4046f3d3eabdd747
Merge topic 'FixValgrindWarning'

cea61bbd COMP: Valgrind detects uninitialized memory read
Merge topic 'PerformanceRecursiveForVariableLengthVector'

a437c3fe PERF: Improve recursive Gaussian perfromance with VectorImages
Merge topic 'book-2-chapter-2-edits-pt2'

5c1310f0 DOC: More chapter 2 edits
Merge topic 'TIFFImproveCompressionSupport'

bb6ea019 BUG: Support TIFF tiled image with TIFFReadRGBAImage
b13c4efe ENH: Query libtiff to determine compression support
Merge topic 'release-ExtractImageFilterCollapseToSubMatrix'

bacb4820 ENH: Add a test on extracted directions in CollapseToSubMatrix mode
ecf0039f BUG: ExtractImageFilter::CollapseToSubMatrix fix