Mapillary inline pictures to iD

This is just a first stab, intended for comments and hints on how to make the behavior nice, please provide feedback!

Demo site: http://mapillary.github.io/iD/
Did some refactoring today to get a cleaner integration into the iD structure, see current code.

Some questions:
- @jfirebaugh the sequences are not updating when panning the map, see above http://mapillary.github.io/iD/#background=Bing&id=w48041386&map=20.00/-77.02223/38.90085 - am I triggering them wrongly with that `projection`?
- also, activating the selectImage mode is still in the layers drawer, even though this is more of a mode now than a background layer. Should there be anything else for activating images?
- need to pull all sidebar interaction into the mode itself, would like the sidebar to display a permanent sticky image at the bottom of the sidebar if one was chosen during imageSelect mode. WDYT?