Author: jim teeuwen <jimteeuwen@gmail.com>
 Dependencies: go-pkg-xmlx ( http://github.com/jteeuwen/go-pkg-xmlx )

 This package allows us to fetch Rss and Atom feeds from the internet.
 They are parsed into an object tree which is a hybrid of both the RSS and Atom
 standards.

 Supported feeds are:
 	- Rss v0.91, 0.92 and 2.0
 	- Atom 1.0

 The package allows us to maintain cache timeout management. This prevents us
 from querying the servers for feed updates too often and risk ip bans. Apart 
 from setting a cache timeout manually, the package also optionally adheres to
 the TTL, SkipDays and SkipHours values specied in the feeds themselves.

 Note that the TTL, SkipDays and SkipHour fields are only part of the RSS spec.
 For Atom feeds, we use the CacheTimeout in the Feed struct.

 Because the object structure is a hybrid between both RSS and Atom specs, not
 all fields will be filled when requesting either an RSS or Atom feed. I have
 tried to create as many shared fields as possible but some of them simply do
 not occur in either the RSS or Atom spec.