FIX #11: private indexes of table
FIX #21: nuke junction_overlap
pull excel_column_label out
FIX #53: move things out of xypath core, mostly
Merge pull request #57 from scraperwiki/21_junctionoverlap

FIX #21: nuke junction_overlap
Merge pull request #58 from scraperwiki/53-excel

53 excel
Merge pull request #56 from scraperwiki/11_private

FIX #11: private indexes of table
no table name in repr(cell)
__eq__ does not test name
no name in CoreBag signature
purge name from signatures
comment: these aren't xypath table names