Sketch initialisation API
Declare an enum for git_delta_t
Sketch a processing block for the file level of the diff.
Sketch GTDiffDelta API.
Sketch GTDiffFile API.
Sketch GTDiffHunk API
Reflect new class structure in GTDiff.h
Update project.
Create hunk initialisation API.
Delta initialisation.
GTDiff initialisation.
Move the declaration of GTDiffFileDelta.
Remove unnecessary `@class`
Add API to fetch the number of deltas of a given type.
GTDiff lifecycle.
Implement delta generation.
Only build deltas once.
Adjust convenience constructors signatures.

Turns out a GTRepository would be a useful thing to have. WHO KNEW?!
Note that we need to settle on an options strategy.
Implement initialisation for 2 trees.