Currently a parser for XLSX files. Cleanroom implementation from the ISO 29500 Office Open XML specifications.
This has been tested on some very basic XLSX files generated from Excel 2011.
*THIS WAS WHIPPED UP VERY QUICKLY TO SATISFY A VERY SPECIFIC NEED*. If you need something that is not currently supported, file an issue and attach a sample file. I will get to it :)
`.SheetNames` is an ordered list of the sheets in the workbook
`.Sheets[sheetname]` returns a data structure representing the sheet. Each key
that does not start with `!` corresponds to a cell (using `A-1` notation).
`.Sheets[sheetname][address].v` returns the value of the cell and `.Sheets[sheetname][address].t` returns the type of the cell (constrained to the enumeration `ST_CellType` as documented in page 4215 of ISO/IEC 29500-1:2012(E) )
XLS is not supported in this module. Due to Licensing issues [that are discussed in more detail elsewhere](https://github.com/Niggler/js-xls/issues/1#issuecomment-13852286), the implementation cannot be released in a GPL or MIT-style license. If you need XLS support, consult [my js-xls project](https://github.com/Niggler/js-xls).