tiny imporve
refactors, remove MFLine and add MFBoundarys
add checkPolygon()
rename GeomModel2D to Polygon2DModel
add fectchLines
partly seperate from Polygon2DModel by GeomModel
source format
add generic segment based range tree searcher
add segmentGetter()
let AbstractModel2Dtask reuse GeomModel's boundaries
add Rectangle2DModel
temperarily blight
refactor, remove GeomModel like duties of RectangleTask
generalize Model2DTask to Common2DTask