Releasing a new version of STD.wy

This is a very minor and inconsequential update to STD.wy which has no effect on
the visible API.  However, a crucial difference is that this WyilFile was
written with a different schema than others (v0.2).  Thus, this is testing
cross-version compatiblity of WyilFiles.

Author: DavePearce

index.txt

@@ -11,3 +11,4 @@ std/0.2.14
 std/0.2.15
 std/0.2.16
 std/0.2.17
+std/0.2.18