Workaround mmap restrictions due to CONFIG_STRICT_DEVMEM

[rbossy]

In systems where the kernel is compiled with option CONFIG_STRICT_DEVMEM, mmap is limited to 1MB: https://stackoverflow.com/questions/8213671/mmap-operation-not-permitted.

The marshalling framework uses mmap with the maximum available size, raising IOException:

bibliome-java-utils/src/main/java/fr/inra/maiage/bibliome/util/marshall/Unmarshaller.java

Lines 150 to 159 in f9b16d9

	public ByteBuffer getBuffer(long position) {
	try {
	long absPosition = startPosition + position;
	long size = Math.min(channel.size() - absPosition, Integer.MAX_VALUE);
	return channel.map(MapMode.READ_ONLY, absPosition, size);
	}
	catch (IOException e) {
	throw new RuntimeException(e);
	}
	}

Solution 1: tell users to recompile kernel. Not always possible.

Solution 2: mmap 1MB only. Problem is that the unmarshalled object might be larger than 1MB.

Solution 3: create a ByteBuffer based on 1MB mmap, but closes and reopens the mmap as needed.