nvd3 and its python/django wrappers appear to be no longer actively
maintained, and at least the wrappers were a bit clunky to use. Looking
around for a suitable replacement, Chart.js seems capable, has no
additional dependencies and is fairly simple to use. As a bonus we get
to drop a few Python dependencies from our list.
Signed-off-by: Paul Eggleton <paul.eggleton@linux.intel.com>
