This PR introduces Microdata tags to com_content in a hardcoded way.
This is based on some feedback that we don't need more parameters.

The PR is based on PR #3252, but unlike this one it doesn't use the Microdata library and instead just hardcodes the tags into the layouts.

Advantage

• Easy to understand
• Easy to change for endusers and designers who like to override a layout

Disadvantages

• You can't enable/disable Microdata tags globally or per contact. You can of course use layout overrides and alternate layouts to achieve the same. It's also to note that there isn't really a reason to turn the Microdata off.
• You can't select a different Microdata type for a contact using a parameter. It's hardcoded to be "Person". You can of course use layout overrides and alternate layouts here as well to achieve the same, but you need to make sure yourself that the properties are valid for the selected type.

Testing

Test the different views of com_contact and check the microdata output using the Google richsnippet test tool: http://www.google.com/webmasters/tools/richsnippets