These leading characters are most commonly associated with number, currency or accounting (or occasionally fraction) formats
git-svn-id: https://phpexcel.svn.codeplex.com/svn/trunk@61632 2327b42d-5241-43d6-9e2a-de5ac946f064
Fixed AdvancedValueBinder date handling (with support for a wider range of date formats), and added support for strings containing numeric values in scientific format (e.g. "-1.234e+5")
git-svn-id: https://phpexcel.svn.codeplex.com/svn/trunk@60740 2327b42d-5241-43d6-9e2a-de5ac946f064