De-duplicate repeated HID packets

[nekomona]

Current implementation of slimenrf-receiver fills empty space with repeated duplication of the last packet to fulfill HID packet length requirement. The duplicated packets would interfere with TPS count and filtering etc.. This PR filters out duplicated packets on the server-side.

[ImUrX]

is it possible to not use a reference instead of copying part of an array?

[nekomona]

is it possible to not use a reference instead of copying part of an array?

I haven't found a method about creating a reference about a part of an array or doing comparison with subarrays, so I tried the way that keeps sliced results being Array<Byte>. I didn't found a reference about how .slice() with List<Byte> would perform but it doesn't seems to be passing by reference to me. XP

[Eirenliel]

If you want to access arrays by references, you need to use ByteBuffers.