Explain the different keystore algorithm between official cli and this one

[QAston]

Either explain it in the readme or add a flag to select the key and select the more secure one by default.

[jenpaff]

sure, will add an argument to make it explicit and give users the option to select between scrypt and pbkdf2 , @mksh should we use scrypt by default then?

EDIT: will use pbkdf2 as default

[jenpaff]

closed with #18