TISTUD-6736 Suggest content assist for string arguments to require function call
  - Quick hack to hook up CA for require call arguments. We ask each require resolver for list of possible module ids in priority order. First one to return a non-null/empty list is what we use for CA.
Add tests for suggesting module ids when we have a node source path and when we don't
Merge pull request #236 from sgtcoolguy/TISTUD-6736

TISTUD-6736 Suggest content assist for string arguments to require function call