Image pyramids

[nfaggian]

We should be able to introduce, with ease, a multi-resolution solver as a wrapper over the existing register.py script.

It might make sense to:

1. add downsample and upsample functions to the registration data.

2. implement an example solver

While I do this I will also:

1. clean up the examples that we have - consolidating them.

2. Investigate using pyqt as a better debugging tool for registrations. I am thinking a custom GUI that lets you inspect each step.

[nfaggian]

Branch made - "ticket_0026"

[nfaggian]

Accidentally closed ;)

[stefanv]

What would you need in a qt viewer? We've got one in scikits.image that could be adapted or improved.

[riaanvddool]

Would be great if the pyramid mechanism would allow factor<1 as well to oversample in addition to the downsampling.

[nfaggian]

Going to look at making an example for the non-linear solver then perhaps will put up a pull request - this adds PyQt to the dependency list for the "searchInspector"....