BUG: itk_tiff.h should not be in itkTIFFImageIO.h

"itk_tiff.h" should not be included in itkTIFFImageIO.h.
It conflicts with other tiff library. Instead it should
be put into itkTIFFImageIO.cxx.

According to "itk_tiff_mangle.h", no tiff headers should
be included in .h files in ITK due to namespace pollution.

Since no tiff header are required in ITK headers, then
also those tiff headers should not be installed by ITK,
this will avoid header conflicts with system level
tiff files.

Reported in: https://issues.itk.org/jira/browse/ITK-2988
by: Linqing Feng

Change-Id: Ib30faae6c4ed6acb1deb79e9cb91004066041fc8
Google double-conversion (reduced)

This corresponds to commit hash

04cae7a8d5ef3d62ceffb03cdc3d38f258457a52

from Google repository

https://code.google.com/p/double-conversion/

Change-Id: I68735b5450bd62e6a8d709475dce9934253d4536
COMP: Merge of DoubleConversion upstream changes.

The update procedure for DoubleConversion is described in
.../DoubleConversion/src/UpdateDoubleConversionFromGoogle.sh

The procedure is based on Brad Kings work, described here:
Modules/ThirdParty/VNL/src/README-ITK.txt

Change-Id: I0c8edc8501cb4a8469a26c2a41df4301457ac977
Merge topic 'DoubleConversion-update'

d466045 COMP: Merge of DoubleConversion upstream changes.
0447797 Google double-conversion (reduced)
BUG: Valgrind error.

The valgrind error that Bill pointed out was
a result of incomplete changes to the code when
I added the ability to specify the shrink factors
per dimension.  The error is definitely one of
the valgrind culprits.

Change-Id: I7e7b19cd25f13c0911b992cf0b5fcf4f8fdb9a25
Merge topic 'itk_tiff_header_polution'

9a539a7 BUG: itk_tiff.h should not be in itkTIFFImageIO.h
COMP: Add missing ImageRegionIterator header in test

Change-Id: Ia9f93b0933fec65f6a0bfb00af679cbadb0bc40f
Merge topic 'FixMissingImageRegionInteratorInclude'

8e86b53 COMP: Add missing ImageRegionIterator header in test
Merge topic 'SyNTestValgrind'

4124933 BUG: Valgrind error.