WayEditor: fix delete support
WayEditor: add tag manipulation functions
RUIAN: multipolygon retrace support
WayEditor: after nodes resurrection, call updateModifiedFlag() on all affected ways

There's a chance that a way is no longer modified because added nodes were
precisely mapped to the corresponding old nodes from original way.
Add GeomDeviation class
Move static geometry functions to GeomUtils
Use GeomDeviation tolerances in GeomConnector routines
Use GeomDeviation/GeomUtils-based routines in clipper
Fix EdMultipolygon.reuseExistingNodes()
Remove reuseExistingNodes' dependency on GeomConnector
Remove connectExistingTouchingNodes' dependency on GeomConnector
Remove all remainders of GeomConnector
Ruian: adaptive reuse of near nodes