Tries to remove all non-UTF8 characters before saving texts
Adds PHP iconv requirement and removes phpexcel extension
Adapts iconv() call for testing
Adapts tests to they create the same result when using PHP 5.3 and 5.4
Disables iconv() test as it doesn't produce reliable results using different PHP versions
Removes iconv() call because it produces unreliable results
Merge pull request #341 from nsendetzky/master

Removes phpexcel extension as requirement