Code Refactoring

[chaithyagr]

This PR does code refactoring based on : #36 (comment)

This will be a big PR and is currently under progress. The work will be done by me and @LElgueddari .

Review will be done by @zaccharieramzi . Adding @zaccharieramzi right now to start off review..

[chaithyagr]

Yaay!!! Coverage increased to 74 percent! This is awesome. We can cross the 80 percent bar as soon as we get a test with dictionary learning also in place.

[chaithyagr]

@LElgueddari can you please add the other calibrationless reconstructions?
I will add an example for self calibrating reconstruction in 2D. You could extend it for other cases that you add.

[chaithyagr]

As this PR is very big, we split it up into #53 #54 #55 #57 .
All the above PRs except last one is in at mainline. At this point, this PR (which was kept for backup incase the split up fails), makes no sense.
Closing this here.