Fix I/O-protocol error handling in eunit

A io_request in eunit reuturns wrong value when it receive getopts or
get_geometry request.
Merge branch 'maint'
Do not attempt to detect lists of printable characters in Data

This is to avoid outputting something like "\"%\f" instead of [34,37,12] in the XML.
Merge branch 'maint'
eunit: Fix silent make rule
Merge branch 'maint'
Prepare release
Merge tag 'OTP_R16B03'

The R16B03 release

Conflicts:
	lib/sasl/vsn.mk