New feature: Edit spots

Edit spots in your local Spotweb database. Allows to change spot title, description, category and subcategories, tags, and website fields.
To be able to control who can/cannot edit spots, a new spotweb security (spotsec_edit_spotdetail (42)) has been added. By default, only admin users can edit spots.
Between the title and watch button, the little pencil button is shown. Pressing the pencil button will popup the edit window (which basically is a copy of the 'add spot' window).