Lock DataSet for RUIAN/LPIS polygon updates
WayEditor framework classes
LPIS: initial rewrite based on WayEditor objects

Generates LPIS landuse (multi)polygons and connects their nodes
to existing landuse nodes.

There's no polygon clipping support yet!
WayEditor: detect old-style multipolygons in filter predicate
Add GPCJ2 polygon clipping library
LPIS: basic polygon clipping experiments
Cleanup polygon clipping class
Remove degenerated tails after clip, duplicate node checks
LPIS: polygon clipping improvements
LPIS: improve clipping, connect touching nodes
LPIS: add multipolygon support to connectTouchingNodes functions
LPIS: Ctrl modifier disables clipping
EdObject: remove unused function
LPIS: reduce point-on-line distance tolerance
Add TODO note
Cleanup pointOnLine() computations
Fix duplicate nodes at the end of clipped polygon
Point-on-line lateral angle was too high
Insert touching node to the closest way segment

If a node "touches" more than one way segment, assign it to
the closest segment. Fixes a bug where multiple nodes near a
sharp polygon corner were incorrectly assigned to the first
available way segment instead of the best one, resulting in
self-crossing way.
LPIS: add clipping that results in multiple outer ways