Prevent Bad file descriptor (Errno::EBADF) Errors on restart when running ruby 2.0 

Ruby 2.0 changed the behaviour of exec to close nonstandard file descriptors by default. This causes Prevent Bad file descriptor (Errno::EBADF) when the files are referenced after the restart. 

This passes in the file descriptors in an options hash to exec to keep the files open.

Fixes #177