Added CRUD page for tags
Changed distribution and taxon concepts to get all tags rather than just
those that have been used before
Removed the "type" column from tags until a good solution for this can
be found
Added tags management link to sidebar
Merge branch 'master' into tag_management

* master:
  added simple manager for events

Conflicts:
	app/views/shared/_sidebar.html.erb
	config/routes.rb
Merge branch 'master' into tag_management

* master:
  Updated spec to match new behaviour in create action of listing_changes admin controller
  Made listing changes form non-remote and redirect to index on create
  Rearranged listing change forms to make them a bit easier to use; moved the current listing changes status to a modal dialog box
  Added information about converting
Added a tags preset model to manage and categorise tags
Added validations to preset tag model
Added specs for TagsController and PresetTag
Removed db/structure.sql from repository
Added db/structure.sql to gitignore
Merged with master. Fixed conflict
Merge pull request #22 from unepwcmc/tag_management

Tag management