init initialise the "repository"

[kzscisoft]

Adds a .fdp folder within the file structure, creates required local configuration file and also record of what is staged. Cannot use FDP without first initialising.

[richardreeve]

I guess as I said in #3, I'm not sure what would go into a folder rather than just a .fdprc file? A user-level init would need to create a folder to set up the place where files are really stored though. I may be misunderstanding the plan though.