DOC: minor issue with the description of the names attribute of multiindexes
BUG: (GH3611) revisited; read_excel not passing thru options to ExcelFile.parse

API: add string and numeric versions of na_values when parsing
Merge pull request #3758 from jreback/parse_na

BUG: (GH3611) revisited; read_excel not passing thru options to ExcelFile.parse