Merge [72000],[72001],[72003], [74691], [75587], [75589], [75590], and [75593]

from trunk.
Fixes bug 4840.
Fixes bug 5259.
Fixes bug 5281, I think.
Fixes bug 5944.
Fixes bug 5757.
Fixes bug 5710.
Fixes bug 5307, I think.

[SVN r76447]

libs/property_tree

@@ -1 +1 @@
-Subproject commit 56cfb6b2f913d84060a6dc98f71c9a166bc58c86
+Subproject commit 9b707a030d4ee16afb1ec696c88f284a67c8ca7f