Remove contractor fields from form, change what prints to PDF - Fix contractor fields part 2

I screwed up the branch from fix-contractor-fields, so updates and merges are done here now.  For reference: https://github.com/codeforamerica/homebase/pull/77

This reformats the enter_details form view completely for homeowners, removing support for contractors completing the process until a later date.

* Remove contractor fields in enter_details view
* Removes javascript we no longer need to support with contractor fields gone
* Drops contractor fields from database
* Moves phone/email inputs into general homeowner part of enter_details form
* Adds new validation to check format on phone number/email, prints validation errors to view
* Prints homeowner name as "contractor" on the permit, per DSD request