[Emacs mode] Add completion by auto-complete.el.
Fixed capitalization error.
Check `o.name` docstring ("doc:" was omitted from comment test)
[node plugin] Don't reuse module instances

Issue #124
Throw error if an unknown plugin is requested
Support specifying unwanted completions with ! prefix in //+ completion test expectations
Failing test of module.exports. and exports. completions including names that are not exported in the current file but were exported by files that the current file requires

bin/test output:

node, line 39: Completion set failed at hint: !mainExport
   got: apply, bar, bind, call, foo, goodbye, hello, mainExport,
secondExport
  args: !mainExport
node, line 40: Completion set failed at hint: !goodbye
   got: goodbye
  args: !goodbye
Ran 288 tests from 33 files.
2 failures!
Fix initialization of match