Make port number a configureable item

Previous version of Postgres.app had port number hard-coded. This version lets postgres and postgresql.conf decide port number. This patch read postgresql.conf and if port number is set, updates port number in the application accordingly. If port number is _not_ set in postgresql.conf, fall back to default port.

Port number is only used for reporting and to set the menu item. Setting port number on the command line is removed. 

In addition, the logic to determine if postgres isRunning is changed to consult the exit code of the process.