Fix real time tracking

If no data came in from the streaming API between to AJAX calls (2
seconds - this can happen when stopped at a traffic light) then
visualize.js would continue on into the future until the end time is
reached. That makes no sense at all, so instead make sure that the
"lastTime" is never later than the "currentTime".

This also fixes the detection of the fake JSON data to recognize the
possible end of the data series.

Signed-off-by: Dirk Hohndel <dirk@hohndel.org>
Add 'Cancel Update' button to map page

This way the user can end the AJAX refresh.

Signed-off-by: Dirk Hohndel <dirk@hohndel.org>
Move some CSS into a style sheet

This will then be used by other pages as well.

Signed-off-by: Dirk Hohndel <dirk@hohndel.org>
Make speedup in the map display dynamic

It can be initially given via a "?speed=..." parameter, or interactively set
via a slider on the map page.

Signed-off-by: Dirk Hohndel <dirk@hohndel.org>
Fix broken map link on the welcome page

Signed-off-by: Dirk Hohndel <dirk@hohndel.org>
Merge pull request #22 from dirkhh/mapImprovements

Map improvements