Run hint script as anonymous object.

This avoids clashes between scripts on pages that defined a variable VbHint.
Moved JavaScript related function to own file.
Changes responsibility for hinting (#61).

The JavaScript handles now the clearing of the hints, so that we do not run
into trouble if the hinting object is overwritten by the next page call before
we are able to run the clear() method on it.
The JavaScript handles also the number filter processing now.