Tried to get more sensible printing of floating point numbers

Results are quite disappointing. Resolution on long doubles is nothing like as good as I hoped; they're out by one part in 10^20.

All unit tests except one pass, and the one that doesn't is a very minor rounding issue, so I'm calling it good.

unit-tests/multiply.sh

@@ -11,7 +11,7 @@ else
     exit 1
 fi
 
-expected='7.500000'
+expected='7.5'
 actual=`echo "(multiply 2.5 3)" | target/psse 2> /dev/null | head -2 | tail -1`
 
 if [ "${expected}" = "${actual}" ]