Absolute path for options #164

Hi, I would like to be able to provide an absolute path for the external data passed to pages,

for example:

panini({
        root: 'src/pages',
        layouts: 'src/layouts',
        partials: 'src/partials',
        helpers: 'src/helpers',
        data: '/tmp/user123/'
      })

Currently it appears that all option paths has to be in the current working directory of the (gulp) process