yubistack 0.4.5

YubiStack implementation

YubiStack provides a simple, integrated re-implementation of: * [yubiauth](https://github.com/Yubico/yubiauth): Authentication client with a simple user management system * [yubikey-val](https://github.com/Yubico/yubikey-val): YubiKey validation server * [yubikey-ksm](https://github.com/Yubico/yubikey-ksm): YubiKey key storage module

##General: YubiStack was initially created to avoid the issues caused by SQLAlchemy running in a multithreaded environment. The yubiauth component was replaced first with a simlified re-implementation. Then the PHP yubikey-val and yubikey-ksm components were rewritten in Python, so we could have native function calls instead of HTTP calls within the stack. To maintain compatibility (and to support distributed systems), WSGI wrappers are available, so all stack components can be still used as web services.