Merge branch 'r0.4.2'

This commit has been tested on my SNSRouter for one month
release v0.4.2
remove notifiers of merge conflic...

   * I remember it has been fixed before... How come..
separate base class
unify all weibo request
special forward for sina
fix forward interface pattern
fix short url
resolve merge confilict with 'dev'
Merge branch 'short_url' into sina-upgrade
move url shortening service to SinaWeiboBase
use unified weibo_request to short URLs
code clean
better tuned special forward: comply to web forward format
fault tolerance for forward