Added Python 3.5 and Nightly to the test matrix.
Added Python 3.5 and Nightly to the test matrix.

Thhhza/XlsxWriter,jmcnamara/XlsxWriter,jvrsantacruz/XlsxWriter,jmcnamara/XlsxWriter,jkyeung/XlsxWriter,Thhhza/XlsxWriter,jkyeung/XlsxWriter,jkyeung/XlsxWriter,jvrsantacruz/XlsxWriter,jvrsantacruz/XlsxWriter,Thhhza/XlsxWriter,jvrsantacruz/XlsxWriter,jmcnamara/XlsxWriter,Thhhza/XlsxWriter,jkyeung/XlsxWriter,jmcnamara/XlsxWriter