Flash loader

Created by: zain-sohail

I am putting this branch for PR so we can soon merge it

The loader is quite complex by nature of the machine, hence the testing will also include such.

It is mostly a porting from hextof-processor with some bugfixes, a change in the multiprocessing backend, a bit of refactoring.

I will keep pushing the tests as I do them but I'd suggest you to review the loader first.