Refs #3395. Optional construction and assignment now works correctly for types with overridden operator&. Also silenced some GCC warnings about broken strict aliasing rules.

[SVN r67020]

libs/optional

@@ -1 +1 @@
-Subproject commit ab01dfff7ee89ac16d3f193e284e2313e036eace
+Subproject commit f88c8ae423c1b164844f07e0ef8800ca11ba3340