Specify particular base image
Specify particular base image

By specifying a particular base image, we ensure the required packages
are available.

We also add packages required for testing all features (i.e. running
`./bin/test -t all`)

mindriot101/rust-fitsio,mindriot101/rust-fitsio,mindriot101/rust-fitsio,mindriot101/rust-fitsio,mindriot101/rust-fitsio