add create_folder_hook

Hi,

I using your plugin redmine_dmsf in another plugin and want to create folders from my plugin. Therefore I add a hook to your plugin.
The call of the hook is

    call_hook(:controller_create_dmsf_folder, :title => "parentfolder", :project => @project, :user => User.current, :subfolder_titles => 'subfolder_one|subfolder_two|subfolder_three')

and creates 4 folders

* parentfolder
  * subfolder_one
  * subfolder_two
  * subfolder_three

It's just an easy way and works not recursive.
The commit c76101e was the merge from version 1.4.8 to 1.4.9. Just the commit **32323cd** contains the changes for the hook.


Regards,
Jens