ECC is slow when signing an API call

[raphaelgodro]

Without any debugger, (in a real mobile environment)
It takes 3-4 seconds to actually to the elliptic curve cryptography and sign a transaction. This is a turnoff in a lot of cases and we need to find a solution to this.

[murray1337]

let's integrate https://github.com/EdgeApp/react-native-fast-crypto
it supports scrypt, secp256k1, pbkdf2 using native speed since it was written in C++