new features

Hello Jaime,

I really enjoyed your ffind project so I decided to fork it after some time using it.
I made a few changes to my fork that I think you could be interested:
- Added the --delete argument to delete files matching search criteria
- Added the --exec argument to execute a command over the files
- Added a backport for argparse to allow it to be used with python < 2.7 

If you like the changes please pull them to your repository.

Thanks and Regards,
Daniel