PARSER: extend the core by the string function
Add PathParser

This allows us to parser user input in order to traverse
the QuadTree from the Algorithms.RangeSearch module.
ALGO: add missing Show instances to RangeSearch
ALGO: export constructors and Zipper in RangeSearch
Add getSquareByZipper function
Update cabal file to include the Parser.PathParser module
DIAG: Allow drawing the square the user path points to
DIAG: clean up squares function