- target locator doesn't use index mapper for polygon points
- deduplicated rings detection logic
- centralized point reduction logic
- deduplicated tooltips building logic

# Conflicts:
#	plot-base-portable/src/commonMain/kotlin/jetbrains/datalore/plot/base/geom/PieGeom.kt
#	plot-base-portable/src/commonMain/kotlin/jetbrains/datalore/plot/base/geom/SmoothGeom.kt
#	plot-base-portable/src/commonMain/kotlin/jetbrains/datalore/plot/base/geom/util/LinesHelper.kt