STYLE: Save deference iterator mapped type to variable

Saving results of require computation is good practice.

Change-Id: I31c3083c8d4e362f2be8faff54ad817687557fa6
BUG: Increase tolerance for itkFEMC0TriangularElement-NodalLoads-BCs

On builds with the -m32 float, different numerical results are obtained
without -ffloat-store (due to differences in floating point precision during
the computation).

Change-Id: I673b10126a54d7b3880f0aa471adbde13d6e0cd0
COMP: Fix checks for system libtiff

The wrong cmake include path variable was used.

CMake's check_symbol_exits requires the result to be fully linked,
which is difficult for libtiff due to possible additional
dependencies on zlib and jpeg. By using check_type_size on the
function name (a pointer), the linking dependency is removed.
The symbol exists in tiff 4.0.3, and requires library.

Change-Id: I46b46af7ee58fcb969e2ba213c542ea1efa955ce
Merge topic 'tiffcheck2'

03b5fd8c COMP: Fix checks for system libtiff
Merge topic 'FEMTolerance'

60d6ea50 BUG: Increase tolerance for itkFEMC0TriangularElement-NodalLoads-BCs
Merge topic 'LabelStatisticsImageFilterPerf'

bc651d8e STYLE: Save deference iterator mapped type to variable