Fix bug where attempting to generate .build .cache folders suppressed error messages

Fix bug where attempting to generate .build .cache folders suppressed
error messages
Fixed bug in GridView::applyFilterAndSort() where needsUpdating is called

GridView::applyFilterAndSort() and GridViewFilterBase::filter() calls
needsUpdating - this causes a needless updating of datasource when no
change to the ui is made
Fixed bug in GridViewListFilter where duplicate filter values allowed

Fixed bug in GridViewListFilter where duplicate filter values allowed
Added bool GridView::canUpdateView specifies if the GridView can update its own view