MOAR Map!!
Full bleed map

More style updates
Auto scroll to bring details into view
Fix postition of zoom controls in full screen map
New Track button
Allow dragging and dropping to reorder tracks
Super Tracks!

Also Drag + Drop Super Tracks
And title editing
Change to event based ui updates
Listen for new sub tracks being added and add table rows appropriately
Remove table row when subtrack removed

Zoom fixes
NaN Duration fixes
Tidy up debug console messages
Only generate thumbnail when its been invalidated

Only invalidate thumbnail when subtracks have changed
- and only if the change is to its points
When points change: update stats and map
When super track is first created it needs to be shown to set up UI
Drag to Desktop!

Needs work - generating gpx on the fly is slow!
Oops merge has not worked since switching to bespoke list implementation:
bcea4f2999

This is fixed now.
Export any supported format
Import any supported format
Support JSON format
Fix bug setting time on multiple tracks