incompatibility with C++ KCP implementation

[DefinitlyEvil]

C++ KCP implementation used little-endian while encoding but this version used big-endian encoding when serializing packets.
I know it's not an issue but it's good to post it somewhere so everyone will know.
thx! ;)

Sincerely,
Tobias.

[RTunSole]

change it in output method：ByteBuffer.wrap(bytes).order(ByteOrder.LITTLE_ENDIAN)

[DefinitlyEvil]

the integers are in LE mode. they must be encoded separatedly.