Fixed 2 bugs: 1 in Client.java, other in README

1. In client.java: replaced several instances of read(byte[]) with
readFully(byte[]) as the first doesn't guarrantee to read the full
array, which might lead to unexpected results.
2. In README: the Java CLI execution line had a typo

Also commented all the ByteBuffer.order(LITTLE_ENDIAN) lines, as they
don't serve any purpose there, and might lead to confusion