ENH: Add variable number of inputs to Dual template

Add the ability to customize the second image template parameter in
the DualImageFilter template. This enables a user settable parameter
to determine the output image type.

Change-Id: I6ae32ebb23ff84fc94dca749559396775b8a6a39
Adding ClampImageFilter

Change-Id: Ibc5349e2762d326dec5bfeab53a60e28a96ffd3b
Adding documentation form ITK XML

Change-Id: Ie2f5fe7382d067dbed478125266fd38923028894
Merge topic 'AddClampImageFilter' into next

97a9e15 Adding documentation form ITK XML
ba0e239 Adding ClampImageFilter
6d04eef ENH: Add variable number of inputs to Dual template