Mention Limnoria requirement in README files ( fixes #198 ).

This adds the mentioning about Limnoria being required to the following plugins.
* (main README.md)
* ChannelStatus
* GitHub ( fixes #197 )
* Glob2Chan
* LimnoriaChan
* WebDoc
* WebLogs
*  Website
* WebStats

Please **tell me** if I forgot some plugin or accidentally made some plugin require Limnoria.