Optional Fields for Update

[rayfarias56]

As the comment near the corresponding TODO suggests. The POST should be moved into BeaconsResource (our current placement doesn't follow REST) This would mean the request would be POST /beacons which would have no URL to conflict with the payload.

Since the PUT option only really worries about updating position we may wish to create a Position object. Not sure about if this one is really necessary.

[rayfarias56]

Commit 0eb782b

Resolves the POST issue. However, The PUT issue isn't resolved. The change to the API should be:

1. Ignore anything the user stated about Id within the payload. It's more "RESTful" to have the URL state which beacon to edit. This means injecting parameters in at the resource level.
2. Edit the SQL implementation to only edit the parameters (x, y, z, description) iff they exist. If they weren't passed in the request's body, leave them unaltered from their current state in the database.

This would now be more closely tied to #19.

[rayfarias56]

We should have all the fields be optional for an update. At the moment we do not.