spline-inverse code conversion to python

[jessdtate]

The spline-inverse matlab code needs to be converted to python. @andycorb has started this conversion, but still a ways to go.

[jessdtate]

@fquivira This is a matlab to python project that is somewhat self contained. It is started, but the code that is converted may not be right. For a fully converted example, you can look at the activation gauss newton example. The MFS inverse may also be helpful as an example for conversion.

[fquivira]

@jessdtate thanks! The Gauss Newton example looks good. Is there an equivalent "main function" for the Matlab spline? Additionally , is there example or test data for validation?

[jessdtate]

It's a conversion from matlab, so there is a working example in scirun4. The example network also needs to be moved over from scirun4 to 5 (issue #28).