ENH: Add multi-Res and multistage registration Examples to ITKv4

MultiResImageRegsitration1 example is converted to use ITKv4 registration
framework along with the related explanations.

Also running a multistage regsitration process is completely
illustrated using two newly added examples to ITKv4.

Change-Id: I1301110a030e76b2c9d811de7303dbfc7c726b2d
ENH: Convert DeformableReg examples to ITKv4 reg framework

This patch convert those DeformableRegistration examples that are used
in registration chapter of ITKSoftwareGuide to the ITKv4 registration
framework, and related explanations are added to the example files.
The metric section example is converted as well.

Change-Id: Ie756b644f855e1b58db90a79a0479d27044c43c6
WIP: convert ImgReg11 to v4

Change-Id: Ib22f2cb06c2f7d811a05c982dfc3bf1f4e36c3e8