Module item visibility

[swfsql]

The API expects some callback implementations, such as for the event functions (eg. OverlayOpened).

ovrt-helper.js declares a function in the global scope, but the one declared by ovrt-sys, is only visible by the module scope.
That item may be exported from the module, and imported into a script on index.html. Such script may also re-export it, but then the consumer would need to import those items.

Currently, to workaround this module scope limitation, an object is created on the global window namespace, and then such object gathers those functions (that need to be exported), which then is used in the re-declaration of such functions in the global namespace.

The workaround works, but preferably the consumer would import the items from the module.