now doesnt try to use <sstream> on g++ < 3, even if it *is* present.

(using strstream for this cas too is just simpler)


[SVN r19984]

libs/format

@@ -1 +1 @@
-Subproject commit 2fc361407fae425f391c2ef8d5a4a7f27da103f3
+Subproject commit bc2bc08695bda9547dcb6dcbf6d8011ae242dc31