Finishing up Sequel adapter for now

Upgraded to sql 4.12.0, and handle connect options. Plus more testing
```
2.0.0-p481 :003 > require 'pg'
 => true
2.0.0-p481 :002 > opts = { :host => nil, :port => 15432, :dbname => 'test', :user => 'nathan', :hostaddr => nil }
 => {:host=>nil, :port=>15432, :dbname=>"test", :user=>"nathan", :hostaddr=>nil}
2.0.0-p481 :004 > PG::Connection.new(opts)
PG::ConnectionBad: could not connect to server: No such file or directory
	Is the server running locally and accepting
	connections on Unix domain socket "/var/pgsql_socket/.s.PGSQL.15432"?
```
Are there defaults kicking in someplace else?