Merge DeltaCode into ScanCode

[mjherzog]

We need to plan for merging DeltaCode into ScanCode Toolkit sooner than later. Since DeltaCode operates on Scan files we should include in ScanCode TK at a minimum in order to treat it as a TK module and keep it in synch with the other TK modules. This will require design especially since ScanCode operates on a pair of Scan files and is therefore not an obvious candidate for running from the main ScanCode command line.

[steven-esser]

We could follow an approach similar to extractcode, which has its own cli command and set of options.

[mjherzog]

This sounds right.

[mjherzog]

Reconsidering whether this is actually a good idea. We probably should avoid over loading ScanCode Toolkit with too many disparate functions.