ENH: Add Set/GetNumberOfThreads for evolution

Change-Id: I74cbecacf48552a4bce038894b3644c161e85416
COMP: Make find_package usage compatible with < CMake-2.8.8

The MODULE option to find_package is a new feature to CMake-2.8.8.
While this option can speed up the find_package command by preventing
a fruitless Config-mode search, it is not strictly necessary.

Change-Id: I28348b29f51508ed72b55c44d3d5a5a7539e2e85
BUG: Two tests were writing to same filename.

These two tests create a tempory file and then read it back in.
The two tests use the same filename for the temporary file. This may
be the cause of some of the test failures on the Dashboard when tests
are run in parallel.

Change-Id: Ib8db714750e92fb3c552988422329cebdc1d07d0
ENH: Otsu code replaced with OtsuMultiple call

Replaced all of the computation code in the GenerateData method of
OtsuThresholdCalculator with an instantiation of the
OtsuMultipleThresholdsCalculator with one threshold.  This ensures
that the two calculators output the same results and promotes code
reuse.  It also enables further enhancements to the computation to be
made in one place instead of two.

It was not possible to make Otsu inherit from OtsuMultiple because
they inherit from very different trees.  This is a separate issue, why
two calculators that compute the same thing have entirely separate
inheritance trees, but this is beyond the scope of this patch.

Change-Id: I4f54c4085bbce3c5eddf62624d4254fe9b294708
Merge topic 'GDCMPositionOrientationTestsTemporaryFilenames'

fecdc6d BUG: Two tests were writing to same filename.
Merge topic 'FindPackage-Compatibility'

7073bca COMP: Make find_package usage compatible with < CMake-2.8.8
Merge topic 'LevelSetv4MultiThreading'

c2bd3fc ENH: Add Set/GetNumberOfThreads for evolution
Merge topic 'OtsuMultipleOtsuMerge'

0aa1d8f ENH: Otsu code replaced with OtsuMultiple call