ENH: Added m_RequiredFractionOfOverlappingPixels to MaskedFFTNCC

Added an argument to the Masked FFT NCC algorithm that enables the user
to specify the m_RequiredFractionOfOverlappingPixels.  This provides an
intuitive way for the user to remove noise pixels on the border of the
correlation image.
It is also robust to changing image sizes because it enables
calculation of the numberOfRequiredOverlappingPixels relative to the
maximumNumberOfOverlappingPixels, which is calculated by the filter.
For example, the user can generally set the argument to 0.1 for most
applications since this will remove the pixels that overlap by 10% or
less of the maximum overlap.
This is also particularly important for odd-shaped masks, where it
becomes difficult for the user to know beforehand how many pixels will
overlap during the correlation process.

The filter header file contains detailed description of the new argument.

Updated tests are provided that use the new
m_RequiredFractionOfOverlappingPixels argument.

Change-Id: Ifbf4ebcc43d49e59040b17140c388199449e01a8
COMP: Remove copy_n wrapper for standard std::copy

This patch address VS2010 not compiling from error in
itkStdAlgorithm.h.

While the interface of std::copy_n is close to how we are using it,
the maintenance and burden of creating C++x11 wrappers should be
avoided. So the usage of itk::algorithm::copy_n has been replaced with
std::copy.

Change-Id: I4cb2aefc759c6dabfea5f455b6f93a0f8a798921
Merge topic 'Repleace_copy_n_with_copy'

e4369d9 COMP: Remove copy_n wrapper for standard std::copy
Merge topic 'MaskedFFTNCCEnhancements'

1d44a59 ENH: Added m_RequiredFractionOfOverlappingPixels to MaskedFFTNCC