bin: make gnode -p &/or gnode -e work properly

Fixes #2
Closes #9.

Squashed commit of the following:

commit 9c6c9cac72c495a7ce6cec1ccddca669636034a9
Author: Tim Oxley <secoif@gmail.com>
Date:   Sun Apr 27 11:36:44 2014 +0800

    Skip -p test in node 0.8.x.

commit 30f65deef3ac0c558565fba23e1c3e36409c1837
Author: Tim Oxley <secoif@gmail.com>
Date:   Sun Apr 27 11:29:00 2014 +0800

    Correctly forward args passed after -p|-e script.

commit 0c599d64bc3050a02debc479e42b4b5f93bff902
Author: Tim Oxley <secoif@gmail.com>
Date:   Sun Apr 27 10:37:39 2014 +0800

    Make gnode -p &/or node -e work properly.

    Fixes #2