[WIP] Fix comments in template literals (#643)

* Add handleTemplateLiteralComment helper function.

* Fix handleTemplateLiteralComment function.

* Extend handleTemplateLiteralComment to deal with trailing comments 🚀.

* Add test.

* Make handle comments function naming more consistent, fix merge conflicts.

* Update tests.

* Add better comment injection in Template Literal.

* Pass options to attach function.

* Update tests to match new implementation.

* Fix let -> var in findExpressionIndexForComment for NodeJS v4.

* Reorder after merge conflicts.

* Drop old tests for dangling arrays.

* Replace redundant conditional by a boolean 🚀.

* Refactor implementation.

index.js

@@ -42,7 +42,7 @@ function attachComments(text, ast, opts) {
   const astComments = ast.comments;
   if (astComments) {
     delete ast.comments;
-    comments.attach(astComments, ast, text);
+    comments.attach(astComments, ast, text, opts);
   }
   ast.tokens = [];
   opts.originalText = text.trimRight();