Attempt to use empty <option> element as 'placeholder' followed by 'placeholder' attribute.

Select's placeholders based on empty '&lt;option value=””&gt;placeholder&lt;/a&gt;' convention are now used , but if possible the current default behaviour to use the 'placeholder' attribute is used. This plays nicer with forms generated as per the convention 'placeholder label option': http://dev.w3.org/html5/spec-preview/the-select-element.html. Also modified '.gitignore' to skip WebDAV cache/control files.