FreeBSD preliminary work.

-) You can't assume bash is installed. Scripts needs to be cleaned out of bashisms.
-) You can't assume python is in /usr/bin. Use env instead.
-) AF_INET is in sys/socket.h
-) Added port_platform's basic structure for FreeBSD, based off Darwin.
-) FreeBSD doesn't have and doesn't need libdl for OpenSSL.