CSV reader used to accept any file without any kind of check. That made
users incorrectly believe that things were ok, even though there is no
way for CSV reader to read anything else that plain text files.
Fixes#167
When describing a cell, the cell reference (r="A1") is optional.
When not present, we should just increment the index of the last processed row.
Fixes#201Closes#225
When the xml file is not a standard xml file, the `simplexml_load_string` will return false, this will cause an error on "$xml->getNamespaces(true);" . So instead of showing the error, we throw an exception.
