adding initial tests, new meeting fields and initial structure

- on UNEP install initial plone content is deleted
- on UNEP install /meetings folder is created
- on UNEP install /documents filefolder is created
- code field of file contenttype is not required anymore
- general tab is being replaced with language_independent
- meeting: address field renamed to location
- meeting: en/es/fr_text field removed
- meeting: new fields:
  - registration_url
  - files_conference_papers
  - files_final_reports
  - files_presentations
  - files_others
  - en/es/fr_announcement
  - en/es/fr_travel_info
  - en/es/fr_visa_info
  - en/es/fr_additional_text