Patch #2477: Added from __future__ import unicode_literals

The new PyParser_*Ex() functions are based on Neal's suggestion and initial patch. The new __future__ feature makes all '' and r'' unicode strings. b'' and br'' stay (byte) strings.
diff --git a/Parser/parser.c b/Parser/parser.c
index 61da37d..8d52153 100644
--- a/Parser/parser.c
+++ b/Parser/parser.c
@@ -202,14 +202,18 @@
 	
 	for (i = 0; i < NCH(ch); i += 2) {
 		cch = CHILD(ch, i);
-		if (NCH(cch) >= 1 && TYPE(CHILD(cch, 0)) == NAME &&
-		    strcmp(STR(CHILD(cch, 0)), "with_statement") == 0) {
-			ps->p_flags |= CO_FUTURE_WITH_STATEMENT;
-			break;
-		} else if (NCH(cch) >= 1 && TYPE(CHILD(cch, 0)) == NAME &&
-		    strcmp(STR(CHILD(cch, 0)), "print_function") == 0) {
-			ps->p_flags |= CO_FUTURE_PRINT_FUNCTION;
-			break;
+		if (NCH(cch) >= 1 && TYPE(CHILD(cch, 0)) == NAME) {
+			char *str_ch = STR(CHILD(cch, 0));
+			if (strcmp(str_ch, FUTURE_WITH_STATEMENT) == 0) {
+				ps->p_flags |= CO_FUTURE_WITH_STATEMENT;
+				break;
+			} else if (strcmp(str_ch, FUTURE_PRINT_FUNCTION) == 0) {
+				ps->p_flags |= CO_FUTURE_PRINT_FUNCTION;
+				break;
+			} else if (strcmp(str_ch, FUTURE_UNICODE_LITERALS) == 0) {
+				ps->p_flags |= CO_FUTURE_UNICODE_LITERALS;
+				break;
+			}
 		}
 	}
 }