Since sim-endian.c doesn't actually use sim_io funcs, it's weird to
include the sim-io.h header here. It's doing so only for the assert
header. So lets relocate the include to the right place.
Two modifications:
1. The addition of 2013 to the copyright year range for every file;
2. The use of a single year range, instead of potentially multiple
year ranges, as approved by the FSF.
