Update from the last version of pyethereum

[javimaravillas]

It is not possible to import the keystore generated with eth_proxy with Geth (1.6.5) or Keyethereum (tested on 5.2, 3.0 and 2.6).

I have done the same test using a keystore from the test of pyethereum last version and it works:

"test1": {
"json": {
"crypto" : {
"cipher" : "aes-128-ctr",
"cipherparams" : {
"iv" : "6087dab2f9fdbbfaddc31a909735c1e6"
},
"ciphertext" : "5318b4d5bcd28de64ee5559e671353e16f075ecae9f99c7a79a38af5f869aa46",
"kdf" : "pbkdf2",
"kdfparams" : {
"c" : 262144,
"dklen" : 32,
"prf" : "hmac-sha256",
"salt" : "ae3cd4e7013836a3df6bd7241b12db061dbe2c6785853cce422d148a624ce0bd"
},
"mac" : "517ead924a9d0dc3124507e3393d175ce3ff7c1e96529c6c555ce9e51205e9b2"
},
"id" : "3198bc9c-6672-5ab3-d995-4942343ae5b6",
"version" : 3
},
"password": "testpassword",
"priv": "7a28b5ba57c53603b0b07b56bba752f7784bf506fa95edc395f5cf6c7514fe9d"
}

[jimkberry]

I suspect all that's necessary here is to update eth_keys.py to match the current pyethereum/tools/keys.py code. Having the code "copied" into eth_proxy that way is a horrible awful thing, but pyethereum is simply too hard to install if you just want to use bits of it. I wish pyethereum had an "extras"-style install to allow installing some of it while leaving out other bits (like eth_proxy does with the "signing" extra).

I should just do this update and see if it fixes everything.