Added postgresql94 package (beta2)

This adds a boxpart for PGSQL 9.4. Currently at beta2 stage.

Notable differences from the current stable 9.3 package:
*  krb5 support has been removed from core
*  make-world is failing for some reason (error 2, couldn't really find any good information in Google about it) so I switched to simply make and install which works fine.

The only other thing with this is, I don't see a way to set a "conflicts" parameter so that this and the current stable can't be installed at the same time. This is something that should probably be looked into if it isn't currently possible. Unless we switch the port that this version listens on. Then they may be able to be installed beside each other.