Handle quoted properties better. Fixes issue 1173
R=dimvar
Rewrite how commonjs exports are handled. Fixes lots of bugs and make them easier to type-check.  Fixes issue 1189
R=dimvar
Revert "Handle quoted properties better. Fixes issue 1173"

This reverts commit 16f7df6d709bab93c3beedf6e27dd5c4dd10fe21.