Meta server: change chunk server token valid time to be exactly 2 hours.
Kfsio library: allow to specify X509 certificate's private key password to support encrypted private key files.
Example configuration files: completed description of all relevant meta server authentication and security configuration parameters. Added description of the authentication session and access tokens lifetime parameters, and X509 certificate and private key parameters description.
Meta server: allow to use simple TLS PSK authentication with chunk server authentication, by specifying shared key. This option is intended for trivial setups with just few chunk servers or for testing only, as it doesn't allow chunk server authentication revocation.