Allow WKT (Well Known Text) input for types

[Ryc O'Chet]

Currently you have to write your query as a JSON object using GeoJSON, but there's also the WKT format, and the corresponding ST_GeomFromText function - it would need a small test to determine if it should be handling JSON or text, but would give more options to users (I find it easier to remember when testing than the JSON formats).

https://en.wikipedia.org/wiki/Well-known_text_representation_of_geometry

[Benjie]

If we can switch to using EWKT on database fetches too, instead of GeoJSON, that’d allow us to expose the M in XYM/XYZM. GeoJSON drops it.