Pure Go Kerberos library for clients and services

 Features:
  - Pure Go, no dependency on external libraries
  - No platform specific code
  - Server Side:
  - HTTP handler wrapper implements SPNEGO Kerberos authentication
  - HTTP handler wrapper decodes Microsoft AD PAC authorization data
  - Client Side:
  - Client that can authenticate to an SPNEGO Kerberos authenticated
     web service
  - Ability to change client's password
  - General:
  - Kerberos libraries for custom integration
  - Parsing Keytab files
  - Parsing krb5.conf files
  - Parsing client credentials cache files such as
     /tmp/krb5cc_$(id -u $(whoami))