Filevector doesn't work on big-endian architectures

[lckarssen]

This is a 'liftover' of bug #5299 from the R-forge bug tracker.

The Debian build logs for big-endian machines (see URL) show that the ProbABEL checks fail on machines with that architecture. Closer inspection reveals that the checks fail on the comparison between text and binary (filevector-format) input.

Also see this discussion on the debian-mentor mailing list, especially Gert Wollny's posts: https://lists.debian.org/debian-mentors/2014/01/msg00326.html
Wollny writes:
"I dug around in the code and voila, e.g. in fvlib/frutil.cpp the
function blockWriteOrRead uses fstream.read|write to do raw data IO and
then in other parts of the code the data is just cast to the desired
type without doing any checks of endianess let alone the needed
conversions."

Since I doubt that many people will use ProbABEL/DatABEL/filevector on other (big-endian) architectures there is no hurry in fixing this. Nevertheless it's worth having this bug visible and in the back of our minds.