[Insight-developers] ContinuousIndex & ContinuousImageFunction

[Lydia Ng]

This is a follow-up to the discussion
on ContinuousImageFunction from last week's tcon.

In my initial design, ContinuousImageFunction
only supported evaluation at a geometric point.

A request was made that it should also support
evaluation at an non-integer position in index space.
Jim suggested a new ContinuousIndex type.

I have implemented ContinuousIndex and have 
checked it in for review.

ContinuousIndex derives from itkPoint. Currently,
it only have a bunch of copy constructors.
Please feel add more functionality.

ContinuousImageFunction,
LinearInterpolateImageFunction and
itkInterpolateTest
have also been updated.


Cheers,
Lydia