Consider implementing delay pools and other protection mechanisms

[uogbuji]

Servers such as Squid and Apache implement delay pools as a mechanism to prevent problematic or abusive request patterns. See also:

• http://www.deckle.co.za/squid-users-guide/Access_Control_and_Access_Control_Operators#Delay_Classes
• http://stackoverflow.com/questions/131681/apache-rate-limiting-options
• http://wiki.squid-cache.org/Features/DelayPools

For now Akara deployments can just lurk behind reverse proxies with such features turned on, but it might be useful to have some primitive facilities for this.