Implements #12, TOTP. This adds support for TOTP to the api and server, with server side token generation, authentication and the correct URI for encoding into QR codes for client token addition. Some extra measures have been taken such as in the stepped auth to always notify on the success or failure of the TOTP first (regardless of order) to prevent PW bruteforce attacks.
Implements #129, pam and nsswitch daemon capability. This is stage 1, which adds a localhost unix domain socket resolver, a ssh key client, support to the server for generating unix tokens, an async client lib, and client handles for adding posix extensions to accounts and groups.
