Fix off-by-one error.
Fix off-by-one error.

Closes #16

NikhilMIT2013/readxl,rdoering/readxl,nvoron23/readxl,rdoering/readxl,warnes/readxl,pozypakya/readxl,pozypakya/readxl,rdoering/readxl,warnes/readxl,nvoron23/readxl,NikhilMIT2013/readxl,warnes/readxl,NikhilMIT2013/readxl,nvoron23/readxl,pozypakya/readxl