spreadsheet-parsexlsx - parse XLSX files

	Commit message (Collapse)	Author	Age	Files	Lines
*	Don't parse sheets where there's no extracted file. See #38	Stuart Watt	2015-09-01	1	-0/+11
	See discussion at: https://github.com/doy/spreadsheet-parsexlsx/issues/38. The patch is a little different from the minimal one suggested initially, because we probably don't even want to return a sheet when we can't parse it.