ENH: Remove vcl_math calls

In the early days of itk development, many c++ compilers treated
math functions inconsistently. The vcl_math routines provided a
platform independent interface. Now, with modern c++ compilers, math
functions are treated more uniformly. This patch removes the vcl_math
calls. The extra layer provided by vcl is no longer needed and may
even cause problems with newer compilers.

Change-Id: I1c39ff4843f690ba220d1c9ccfd40fd6549188af
Merge topic 'Remove_vcl_math'

f48d80c4 ENH: Remove vcl_math calls
ENH: Convert the ImageRegistration3,4,5  examples to ITKv4

Three registration examples are refactored to use v4 registration
framework. Also, the explanations related to the deprecated features are
remove, and new explanations are added to reflect the new features.

Change-Id: Ia6513dc15869bf6b29ac508e481e86212e9aa396