Added psync(port sync), updated puni, puo

Added psync(port sync) to performs a sync operation only on the ports tree of a MacPorts installation, pulling in the latest revision available of the Portfiles from the MacPorts rsync server.
Added -u option to puni,puo so that it uninstall non-active ports when upgrading and uninstalling.
#### If I use -u within the upgrade outdated  command I need not run uninstall inactive separately like below.
```
[~ZSH/plugins]$ puo                                                                                                                         [master][ruby-2.1.1]
--->  Computing dependencies for gettext
--->  Fetching archive for gettext
--->  Attempting to fetch gettext-0.19.1_0.darwin_13.x86_64.tbz2 from http://packages.macports.org/gettext
--->  Attempting to fetch gettext-0.19.1_0.darwin_13.x86_64.tbz2.rmd160 from http://packages.macports.org/gettext
--->  Installing gettext @0.19.1_0
--->  Cleaning gettext
--->  Computing dependencies for gettext
--->  Deactivating gettext @0.18.3.2_0
--->  Cleaning gettext
--->  Activating gettext @0.19.1_0
--->  Cleaning gettext
--->  Computing dependencies for gnutls
--->  Fetching archive for gnutls
--->  Attempting to fetch gnutls-3.3.4_0.darwin_13.x86_64.tbz2 from http://packages.macports.org/gnutls
--->  Attempting to fetch gnutls-3.3.4_0.darwin_13.x86_64.tbz2.rmd160 from http://packages.macports.org/gnutls
--->  Installing gnutls @3.3.4_0
--->  Cleaning gnutls
--->  Computing dependencies for gnutls
--->  Deactivating gnutls @3.3.3_0
--->  Cleaning gnutls
--->  Activating gnutls @3.3.4_0
--->  Cleaning gnutls
--->  Computing dependencies for openssl
--->  Fetching archive for openssl
--->  Attempting to fetch openssl-1.0.1h_0.darwin_13.x86_64.tbz2 from http://packages.macports.org/openssl
--->  Attempting to fetch openssl-1.0.1h_0.darwin_13.x86_64.tbz2.rmd160 from http://packages.macports.org/openssl
--->  Installing openssl @1.0.1h_0
--->  Cleaning openssl
--->  Computing dependencies for openssl
--->  Deactivating openssl @1.0.1g_0
--->  Cleaning openssl
--->  Activating openssl @1.0.1h_0
--->  Cleaning openssl
--->  Updating database of binaries
--->  Scanning binaries for linking errors
--->  No broken files found.
[~ZSH/plugins]$ sudo port -u uninstall inactive                                                                                             [master][ruby-2.1.1]
--->  Uninstalling gettext @0.18.3.2_0
--->  Cleaning gettext
--->  Uninstalling gnutls @3.3.3_0
--->  Cleaning gnutls
--->  Uninstalling openssl @1.0.1g_0
--->  Cleaning openssl
[~ZSH/plugins]$
```