File input flag about json_repair

[mangiucugna]

Hi! Feel free to push a PR for this, I think it should be implemented as a new function called "load_file" in which the file is read and then repair_json is called.
Of course all the repair_json params should be exposed as well.

[mangiucugna]

Hi, in the end I went in a sligthly different direction and done two things:

• implemented the drop-in replacement for json.load()
• added a new function from_file() that take a file path as string
  To respect the behavior of the json library no exceptions are managed in the library but left to the caller

Thanks again for the contribution and ideas!