Fix #372: Don't protect reciever when calling js.Dynamic.x
Merge pull request #380 from gzm0/fix-js-dynamic-protect

Fix js dynamic protect
Fix #370: Disallow export of local methods / variables
Fix #369: Test prohibition to export names containing __

This already worked (unlike what the ticket said). This commit only
adds the relevant test.
Merge pull request #382 from gzm0/bugfixes

Bugfixes