Wang–Müller line simplification algorithm in PostGIS

Motiejus Jakštys d6f90a3ffb somewhat similar result in one of the test cases		2021-05-19 22:57:45 +03:00
db	more elaborate test cases	2021-05-19 22:57:45 +03:00
notes.txt	wip demo self-crossing: it's now incorrectly mutating things	2021-05-19 22:57:45 +03:00
tests.sql	debugging	2021-05-19 22:57:45 +03:00
wm.sql	somewhat similar result in one of the test cases	2021-05-19 22:57:45 +03:00