Carried on with AMATSelectAction

It now works, but only selecting a rectangle around features.
Probably a simpler InfoAction that opens a dialog with the feature details would be better,
but then a specific action will be needed to support cases where matching between OSM and AMAT Ways
is impossible using Nodes (they're too far apart and the OSM geometry is correct)...
Reduced buffer size when searching for AMAT Nodes. FIXES #4

When encountering this problem it's possible to move the OSM Node closer to the correct AMAT Node and away from others,
so that the tool should be able to find only the correct one.
It is possible though, that in very dense Nodes situations, it can not work anyway...