fix #113; replaced "[1.8," with "[1.8,)" in parent pom  profile 'doclint-java8-disable'
start of new SPI OO interface and impl; work in progress
new SPI impl; untested
updated license headers
replaced 'Arrays.copyOfRange()' with 'System.arraycopy' to avoid resulting arrays with padded zeros.
removed InputStream.close(); we should not be closing the stream here
added static method to derive SpiChannel enum instance from raw number
updated PiFace impl to use new SPI OO interface
updated SpiExample to use new SPI interface