Files access rights set to 644
Basic TDD setup in place :
- SimpleTest installed (outside our workspace)
- Basic file creation test
- SpreadsheetML schema validation (DTD available in SpreadsheetML directory)
  (Warnings are ignored)
Better class name for this test
Created function to add additional sheets
newSheet($name)
Data writing test in multiple worksheets
Data must be written sequentially, there is no way to write data to the first sheet when the second has been added.
Added   <?mso-application progid=\"Excel.Sheet\"?> to the XML header
so the .xml file is opened in Excel on a double click
Revert "Added   <?mso-application progid=\"Excel.Sheet\"?> to the XML header"

This reverts commit 7c932833888ac3242cd4a2e84cb42c0804947a09.
Added   <?mso-application progid=\"Excel.Sheet\"?> to the XML header
so the .xml file is opened in Excel as a default
Improve numbers detection heuristics (i.e. allow decimal dot)
oops missing encoding value in header
Remove now unnecessary \ before " quotes.
Encode \n into &#10;
Define a Multiline style
Apply it to cells with a \n
Cleanup
Multiline test
- use is_numeric for Number type detection
- allow forward slash in date
- removed unnecessary timestamp checks
improve datetime regexps

based on discussion from here:
https://github.com/elidickinson/php-export-data/commit/c00f622d24f833c35b6a45d89dd49098865b41ee#commitcomment-1887500
- more precise date/time matching
- allow only numbers in format "2", "2.5", "2,5" and convert comma to dot
- test cases for numbers and dates
Added ability to use the thousands separator in excel
Support multiple sheets

* addWorksheet(sheetName)
Merge remote-tracking branch 'remotes/merge1/master'

Conflicts:
	php-export-data.class.php
Merge remote-tracking branch 'remotes/merge2/master'