Fix issues with parsing ISO 8601 dates in IE8

This is a dirty fix for IE8 not parsing [ISO 8601 dates](http://msdn.microsoft.com/en-us/library/ie/ff743760.aspx) properly.

Fix was taken from: 
http://stackoverflow.com/questions/3046459/ie-date-parse-method-returns-nan-for-date-with-time-string