ENH: add Set/Get initial parameters to ITKv4 registration framework

Currently the only way the initialize the registration configuration is
to set up an initial moving transform. Inside the registration filter,
this initial transform is added to a composite transform along with the
output optimizable transform, and this composite transform is used for
metric evaluation at each iteration.

In this case, we also need to use a composite transform after the
regsitration process to concatenate the initial moving transform and
the output of the registration filter to create the final transform for
the resampler.

Doing all above is a lot more work that is necessary in many cases.

In this patch new APIs are added to the ITKv4 registration framework
that allow us to directly initialize the output optimizable transform.

These new API is called "InitializeOptimizableParametersFromTransform",
and it provides a new option for iniatialization of the registration framework.
This feature lets us to initialize the optimizable registration transform
directly in a same way as we used to do in ITKv3.

Change-Id: I49a1ee0fd88e289bbc266ea61e68d6d0968fd761
DOC: The use of VersorTransformOptimizerv4 is deprecated.

The use of this optimizer can be replaced by the
RegularStepGradientDescentOptimizerv4 that can generate more precise
results on versor transform optimization.

Change-Id: I987d237f35a2affa5d7b791b34cfeb8d7b37fa7b