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
Merge topic 'itk_tiff_header_polution'

9a539a7 BUG: itk_tiff.h should not be in itkTIFFImageIO.h