Get user's location in the same way as friends'.

Try to lookup in table, if failure then geocode. Also add some error
checking around the location and the coords, which was absent before.
Add user's location/coords to location hash.

Same process as with friends; might as well not duplicate effort here,
too, because the user will no doubt share their location with at least
one friend. Now have some repeated code that should be factored
out. Also getting some geocoder errors -- they are silent (return nil
for coords) but I don't quite get what's happening.