Update README.md

Adding a description for the RSA keys.

Update [RSA.py] {v4.1} [KRIS.py] {v1.3}

# RSA
- Correcting a small bug in `RsaKeys.__init__` : when using a string for the key name it now works ;
- Adding color for some error messages in console mode.

# KRIS
- Adding method `encryptFile` and `decryptFile` to encrypt and decrypt files with KRIS cipher, but not used in Cracker.

Update README.md

Delete elerias.pbk-d

Removing the clear keys files