Smashing new features

• Added following middleware
  • Panic recover
  • Basic auth
  • Strip trailing slash
  • Redirect to slash
  • Gzip
• Support to serve favicon
• Enhanced priority in router
• Wrapped Flush, Hijack and CloseNotify functions in response.
• Fixed issues: #51, #53, #57, #63, #65, #67, #68
• Dropped NotFoundHandler in favor of HTTPErrorHandler