DataInputStream/DataOutputStream modified UTF-8 has incorrect encoding

[XerTheSquirrel]

The modified UTF-8 that these methods read and write are not done so correctly and will result in compatibility issues outside of ASCII.

The length of the string in characters is read/written where it should be the number of bytes used to represent the modified UTF-8 stream. This will work for ASCII but will break if NUL or anything higher than character 127 is used.