ByteContainer.setBytes: fix arraycopy length discrepancy

[comotion]

if length < data.length, the byte should be cleared and the new values
should be right-adjusted. Otherwise, the container no longer represents
the bytearray/BigInteger correctly.

See #209

[martinpaljak]

https://github.com/martinpaljak/jcardsim/blob/next/simulator/src/main/java/com/licel/jcardsim/crypto/ByteContainer.java#L119

[comotion]

https://github.com/martinpaljak/jcardsim/blob/next/simulator/src/main/java/com/licel/jcardsim/crypto/ByteContainer.java#L119

The this.length = data.length change is important because otherwise the length is incorrect when the container is resized, causing intermittent crypto failures. I see the linked code is missing that line.

@martinpaljak nice to see your fork. Are you interested in other PRs, like for instance reconnect support in the VSmartCard interface?

[martinpaljak]

@comotion If that would be missing - yes. There's not yet public usage guide documentation, but I would expect "plausible UX" in the end.

[martinpaljak]

I've not yet reached the point where I look at the implementation of crypto functions, the XXX comment shall disappear when I do.