Round decimal division of tuple elements.

When performing tuple division, the floating point representation of
decimal divisors may yield surprising results.  For example, the
following expression

  >> 1.1.1 / 0.1

can return 9.9.9 or 10.10.10 depending on the host platform.

To address such discrepancies, `round(3)` before casting the result of
tuple element division to a `REBINT`; this should improve cross-platform
consistency.

src/core/t-tuple.c

@@ -232,7 +232,7 @@
 			case A_DIVIDE:
 				if (IS_DECIMAL(arg) || IS_PERCENT(arg)) {
 					if (dec == 0.0) Trap0(RE_ZERO_DIVIDE);
-					v=(REBINT)(v/dec);
+					v=(REBINT)round(v/dec);
 				} else {
 					if (a == 0) Trap0(RE_ZERO_DIVIDE);
 					v /= a;