Merge pull request #421 from dwrensha/bad-double-far

Edit error message for the case where copyPointer() hits a FAR pointer.

c++/src/capnp/layout.c++

@@ -738,7 +738,7 @@ struct WireHelpers {
         break;
       }
       case WirePointer::FAR:
-        KJ_FAIL_ASSERT("Unexpected FAR pointer.") {
+        KJ_FAIL_REQUIRE("Unexpected FAR pointer.") {
           break;
         }
         break;
@@ -1872,7 +1872,7 @@ struct WireHelpers {
       }
 
       case WirePointer::FAR:
-        KJ_FAIL_ASSERT("Far pointer should have been handled above.") {
+        KJ_FAIL_REQUIRE("Unexpected FAR pointer.") {
           goto useDefault;
         }