Fix daemon to respect 'access' prop on project user list

Right now, we just check to see if a user is in the list of maintainers for a project. This is not correct, as being in the list is insufficient - the 'access' prop has to be set to 2 (ALL). We could make that property and the reason for it a little clearer, but it's not really worth fixing right now.

However, because PHP is annoying, there were a lot of ints coming through as strings, and they needed to be converted to ints. So there's a commit in here that also ensures that, when converting from JSON, any string that contains a valid int (that is, for which `isdigit()` is true), is cast to an int.