Updating res.sendfile to res.sendFile (and added root path)

This suppresses the warning stating that res.senfile is deprecated in favor of the new res.sendFile.  The new command (res.sendFile) requires that a root path be added also, so I've done that as well.
Merge pull request #7 from grese/master

Updating res.sendfile to res.sendFile (and added root path)