Initializing a pyVolume object by fitting to the baseline data does not work.

[anilyil]

Description

The least squares fit based initialization of volumes don't work, OR the test that was using this initialization was broken. The original data that looks like this:

results in a pyVolume object that looks like this:

Either the functionality is broken, or the test was written incorrectly. Either way, I removed this approach in #47 and opened this issue. This should be tested to make sure the initialization fit works as intended. Then we need to add this back to the tests. For now, I am creating the test volume by directly providing control points.