Use Webrick instead of Thin.

Eliminates one dependency, prevents a nasty segentation fault.
Merge remote-tracking branch 'origin/topic/bf_use_webrick' into develop

* origin/topic/bf_use_webrick:
  Use Webrick instead of Thin.
Release version v0.2.5-rc047.
Initial work on adding file access right management.
Gives access to files with role "default".