Support microdata in video module

http://drupal.org/project/video

Problem/Motivation

For HTML elements with a src attribute, such as video, or a data attribute, such as object, the microdata attributes have to be placed within the element itself. This means that microdata module will need to pass the microdata attributes to the templates, which are placed in sites/all/modules/video/theme.

Proposed resolution

1. Add the property information that is required by Entity API. Properties should potentially include some metadata. For example, http://schema.org/VideoObject exposes the encodingFormat (i.e. mpeg4)
2. Use hook_microdata_value_types_alter(&$types) to change the value type to 'item_option'.
3. Figure out how to get microdata attributes from the formatter code to the template and place it on the video tag.
4. If metadata is included, add that to the templates in meta tags, conditional on whether microdata exists for them.
5. Add a suggested mapping based on Schema.org

Remaining tasks

Everything ;)

User interface changes

Microdata box and suggestions radio will be added to the bottom of the field settings page.