Events plugin

Testing events and locations plugin.

So we now have a plugin here for events and locations. Its enabled in the calendar, regional, and nzlarps categories at the moment, as these are the categories most likely to use it. We can enable it in other categories too if its wanted.

Apart from being able to provide dates/times and locations for events, to also provided 2 new views on a category: an agenda view that lists events, and a map view.