== Potlatch 2 refactoring ==

Aims:
- to enable multiple Maps to be shown on-screen (e.g. for junction editor)
- to bring Connection and VectorLayer code together

==== think what to do about controllers ====


Map.as changes:
becomes a collection of MapPaint objects, all with the same lat/long/scale
(plus a backdrop sprite and a background imagery sprite)
√ move listeners to Connection to MapPaint (e.g. new way created in the Connection - MapPaint should know about it, not Map)
- refactor tileset/setbackground stuff?

MapPaint.as changes:
- gains a reference to a Connection - i.e. the source data for this layer
- needs an 'interactive' flag
√ UpdateEntityUIs no longer needs a set of entities passing to it - it can read directly from the Connection
- consider whether it's better to have a backreference to Map or for Map to update edges/lat/long/scale etc.
- wayuis, nodeuis etc. should ideally be private
- removeLayer should blank

VectorLayer.as changes:
- move into Connection

Global changes:
- remove all references to getConnection etc. - there can now be more than one Connection
- remove all back-references to Map except where necessary for lat/long/scale
- Controllers are full of references to controller.map and to controller.connection
- move AttentionEvent stuff