Cleaning some functions in DAOs and webservices. Deleting useless files.
Adding tag functionalities : friends in friends lists contain tags now,
and tags can be changed by sending a friend with a tag list + all the
tags are visible with a GET at /tags.
Merge pull request #44 from fbouquet/cleaning_webservices

Cleaning some functions in DAOs and webservices. Deleting useless files.