tests: run render tests with internal template engine
examples: switch examples used in tests to ejs engine
build: remove support folder
deps: connect@2.27.6
deps: istanbul@0.3.5
deps: should@~4.3.1
3.18.5
Fix exception in req.fresh/req.stale without response headers

fixes #2468
3.18.6
Merge tag '3.18.6'