Specify address format to user

Currently we have meeting_address1 and meeting_address2 columns in the database, to match the standard US address format. But, Google Maps' API doesn't accept building names or room numbers very well. So, we need to make the data format of these two columns more specific and explain that format to the user in the form where they will enter data about a congregation.

Specifically, we should change the names of those fields in the database (via a database migration) to:

meeting_address
meeting_address_building_or_room

and change the references to those database columns throughout the code.

And, explain these fields to the user by giving them these titles, followed by these examples, in a form:

Meeting Address (e.g., 100 E Main St)
Building or Room (e.g., Old Sanctuary, Room 29, YMCA Gymnasium, High School Auditorium, etc.)

Note these horrors of address format inconsistencies: http://www.mjt.me.uk/posts/falsehoods-programmers-believe-about-addresses/