chore(Directive): clean up code for clarity/style.
fix(directives): cssUrl in NgComponent

Closes# 418
Revert "chore(scripts): In env.sh don't assume that ./dart-sdk exists "

This reverts commit 4b121eed4cfe20fc34de4f5fda4a6c639428b8af.
feat(parser): Allow operator access to non-map, non-list objects

Closes #416