Move Log class under Core engine
Move UploadsController to the Frontend engine
Remove rubyzip dependency (now in dradis-projects)
Fix dradis:reset Thor task

Most of the problems were down to:

* Model namespaces (e.g. Attachment vs. Dradis::Core::Attachment)
* The Dradis::Plugins::Projects plugin changes

See:
  http://github.com/dradis/dradis-projects
Update schema.rb after dradis_logs creation