Contributed by MAEDA, Go

Added view hook for additional wiki formats [refs #488]

Conflicts:
	app/views/help/wiki_syntax_detailed.html.erb
	public/favicon.ico

Conflicts:
	lib/redmine/scm/adapters/subversion_adapter.rb

* Allows plugins to add to the list of supported export formats at the
  bottom of the Wiki#show view template

  undefined method `logged?' for nil:NilClass

Using 3c2ef2757165e23b65fd from
https://github.com/edavis10/squeejee_theme/tree/chiliproject.org