Move HTML source into a separate file

Load the file and replace some MAGIC_ values with the correct data at runtime.
With this there's an easy to edit and maintain 'map.html' file that gets used
as the basis for the file served.

Also extend the window for searching for timestamps to ten minutes (as I found
two instances where there was a gap of more than five minutes in my data).

Signed-off-by: Dirk Hohndel <dirk@hohndel.org>
Add simple energy display

The URL needs to be of a rather inflexible format - I'm sure we could write
much better parsing for different ways to specifying the date. For now you need
http://localhost:port/energy?from=year-month-day-hour-min&to=year-month-day-hour-min

Signed-off-by: Dirk Hohndel <dirk@hohndel.org>
Add crude favicon

This is loosely based on the Tesla flag.

Signed-off-by: Dirk Hohndel <dirk@hohndel.org>
Add the flot chart JS file to the repository

This is the latest version (as of this writing) from http://www.flotcharts.org/.
It's under the MIT license so we can easily add it here. Alternatively we could
add instructions how to install this from the original site.

Signed-off-by: Dirk Hohndel <dirk@hohndel.org>
Add energy/speed graph to the README.md

Signed-off-by: Dirk Hohndel <dirk@hohndel.org>
Merge pull request #3 from dirkhh/energy

Added Energy Chart