* Read Code Page for Xls ListWorksheetInfo/Names for BIFF5
Fix#3671. Xls reader was not processing Code Page as part of functions ListWorksheetInfo/Names, which was causing them to fail for for BIFF5 (and BIFF7); this was not a problem for BIFF8. There were no unit tests for these functions for either BIFF5 or BIFF8. There are now.
* Add getVersion and getCodePage Methods
These came about because test file for non-standard codepage was supposed to be BIFF5, but turned out to be BIFF8 using UTF-16 with some string data otherwise encoded. Add a BIFF5 equivalent (some hex editing was required), and the means to distinguish one from the other.
* Found MACCENTRALEUROPE Text in BIFF8
It was used for 'Last Modified By' property, even though bulk of spreadsheet uses UTF-16LE. Add a test.