Removed bbox array look-up in _list/bbox-filter.

I do not see how this wouldn't get us lightning speed!!!
Removed unsignificant digits from errors listing.

This way the geometry lookup using _view/geojson is more reliable because I can
thrust the error given by _list/bbox to be correct.
The raw view output still reads "errors": [0.0004299999, 0.00017000001, etc.],
because it seems that numbers are converted to floats, then to a string
representation, and then added to the index.
Removed documents with no type from some indexes.

If a document contains geometry, this is fine and I can still reference to it.
I would like to use hidden documents for internal links in the near future and
I don't want to assign an extra type for those.