Fix user click through bug

There was a bug where if you clicked on a user icon to checkin it would
not register the room below it.

This is fixed with the pointer-events CSS property
Fix user checkin position offset

There was a bug where the checkin cursor would point to the top-left of
the user.

This is now fixed by offsetting the user avatar so that it is centered
over the checkin position.
Add support for multiple floorplans

This commit adds support for multiple floorplans.

Currently there are two floorplans:
* Causes office
* Other areas

This allows us to include other "rooms" like a coffee shop or home, so
people can checkin there.

This required some slight restructuring and adding of a new Floorplan
model.

Floorplans now contain multiple rooms.

Checkin coordinates are now room specific so that we can render users
within rooms of different floorplans.

The JS has been updated so that you can now only checkin to a room
directly (not a floorplan).
Rename Floorplan to Area

This commit renames the Floorplan resource to Area.

This is done to make it more general because we're starting to expand to
checking in to zones that aren't necessarily rooms that are part of a
building.

The next step is to rename Room to Zone.
Rename Room to Zone

This commit renames the Room resource to Zone.

This makes changes both the schema and all the models, views,
controllers, helpers and assets.

This is part of a new naming scheme which abstracts the concepts a
little more so they're not tied to rooms of a building but can be used
to represent any zone that you can check into.

All zones are part of an area.