Add setter/getter callbacks for entity properties

edit: this patch is missing the options callback so ignore it, its no good.

Woops forgot to merge in the options callback. Here is a working patch.

Did you try using the 'set data value' rule on any of the properties all the way to completion? When I tried, after selecting a particular property and clicking continue, it brought me back to the same selection screen with a message "status cannot be set" or something like that. Also, I found that not all the properties were present in the list.

Here is a test:

Use an event like 'Reply is saved'
action: "set a data value" - choose 'status' from the data selection widget.
click continue
You should now see the error regarding not being able to set it.

This same error is received for all the properties as far as I can remember.

The patch also adds a options list callback for entity types rather then having to type in the machine name of an entity type.

I was able to create a reply through rules using a create entity rule in combo with a series of set a data value to select the entity type and entity id properties, etc.

Hope that all helps.

I'd like to point out that this isn't just a rules thing. It will also help in views integration, VBO, view modes, custom edit interfaces for replies that another contrib module developer may wish to create, etc.