Added feature to authenticate with email, password and two-factor code to approve a SIN, and added various prompts to commands.
command nomenclature
command nomenclature helptext
moved BitPayUtils to lib/cli-utils.js and used hashPassword from libs
Merge pull request #34 from braydonf/feature/register-sin-two-factor

Added feature to approve client identity with email, password and two-factor code with command ′keyapprove′