Fix for issue #7.

Squashed commit of the following:

commit b432478d033c0b09a31a1acf1b80714fb53d0cf3
Author: Andrew Crichton <andrew.g.crichton@gmail.com>
Date:   Mon Mar 31 15:24:50 2014 -0400

    Ensure consistent background colour.

commit ef421b49d958e27b60ed2e05626cbeec3642839e
Author: Andrew Crichton <andrew.g.crichton@gmail.com>
Date:   Mon Mar 31 14:59:31 2014 -0400

    correcting erroneous draw