Enhance fqsort function to accept a temporary directory parameter for file handling. Update calls to fqsort in main.cpp, sort.cpp, sort.hpp, and unit.cpp to utilize the new parameter, ensuring temporary files are created in the specified directory.
* Start of externalizing polygon shard detection
* Completely untested external quicksort
* Add unit test for external quicksort
* Remember to clean up temporary files
* Sort and scan the vertices
* Bring over more vertex logic
* Make nodes from vertices
* Checkpoint on switching over to global shared nodes
* Do the thing
* Revert unintended change to coalesced linestring behavior
* Take shared nodes into account in early simplification
* Let it do more sorting in memory
* Fix overnoding of collinear linestrings
* Remove duplicate nodes, since only duplicate vertices now matter
* Remember to delete temporary files
* Fix out of bounds memory access below, apparently
* Fix the actual undefined behavior
* Still running out of memory in one case. Find out where.
* Forgot the conditional
* Try again to make it not run out of memory
* Update version and changelog
Mike Jones