swap argument order again
swap argument order again

On my Raspberry Pi, the previous version was better with GCC and
with Clang. However, on my laptop i7 with msvc110, this version is
better. I should still test my desktop i7 with Clang and GCC though,
because previously it turned out that msvc generates far-from-optimal
code, so I might have to reverse it again.

ruud-v-a/fibint