Add and enable "include current location in routing?" toggle

[LanesGood]

• [x] Include current location as a marker on the map
• [ ] style current location marker differently
• [x] render current location as a preview item
• [x] allow click on current location preview item to fly map to current location marker
• [x] toggling off current location removes marker from map, preview item and current location coords from routing coords array
• [x] removing current location preview item toggles current location toggle

[LanesGood]

Additionally:

• [ ] Style current location preview item differently

[LanesGood]

Completed - will close rest of items with #17