[josm-dev] [PATCH] validator enhancements

[Dave Hansen]

A bogus version of the TIGER data converter once created empty nodes.  I
figure we might as well have a check for those.

The TIGER data creates duplicate nodes for things like when a power line
and a highway share an intersection.  This modifies the DuplicateNodes
validator plugin to check a node's type by seeing to which ways it
belongs.  (getType() needs some definite enhancement here).  If two
nodes have different types, we don't report them.  

Finally, create a "MotorwayIntersections" checker.  It ensures that
motorways only have intersections with other motorways or motorway
links.

This patch also contains support for returning success/fail from
Command.executeCommand() functions.

-- Dave