Use leaflet-hash
Redirect lat/lon/zoom query params to hash
Prefer hash to other methods of determining location
Refactor URL generating methods
zoomPrecision doesn't need to be higher-order
Generate hash-based permalinks
Update hash on P2 and iD edit pages and throttle
Include layers in hash
Make the multi-get calls throw 400 errors on invalid input

Also refactor ways and relations to use the same structure as nodes
Add functional tests for nodes/ways/relations API methods
Merge remote-tracking branch 'osmlab/hash'
Update user location setting for zoomPrecision change
Update short link integration tests for hash links
Reorganize share/export UI

"Image" and "Embeddable HTML" options move to share control.
Only XML export remains, and is now accessed via a sidebar
link rather than the tab bar.
Add option to include marker in permalinks
Link to sources for bulk downloads
Remove marker and filter when closed
Recenter marker when shown
Fix textarea resizing
Tighten vertical space