- add a separate signature for [swizzle] to explicitly allow void columns with a nil seqbase
- add a separate signature for [swizzle] to explicitly allow void columns with a nil seqbase

zyzyis/monetdb,zyzyis/monetdb,zyzyis/monetdb,zyzyis/monetdb,zyzyis/monetdb,zyzyis/monetdb,zyzyis/monetdb,zyzyis/monetdb,zyzyis/monetdb,zyzyis/monetdb