Yet Another Pragger implementation

 Yapra is yet another Pragger implementation. Pragger is a pluggable RSS/Atom
 feed aggregator written in Ruby. It has following advantages
 against Pragger.
 .
  * Class-based plugin mechanism
  * Loadpath-based plugin searching/reading
  * Import logger into system core
  * Use "Yapra" namespace for Plugin class
  * Support config file like Python habu