Fix stride related bug in Canvas immediate API
Add test case for 3D geometries in immediate API
Merge pull request #2255 from elemoine/complexgeom

Fix canvas immediate API for cases where stride ≠ 2
Also accept empty array for ol.geom.MultiPolygon
Safeguard against cases where no projection and no proj4 is available
Merge pull request #2329 from tsauerwein/multipolygon-empty-array

Also accept empty array for ol.geom.MultiPolygon
Merge pull request #2330 from ahocevar/proj4-global

Safeguard against cases where no projection and no proj4 is available
Check for proj4 in a way that also works in module environments
Merge pull request #2333 from ahocevar/better-proj4-check

Check for proj4 in a way that also works in module environments