Merge quickbook from trunk.

- Use a single symbol table for all elements.
- Fix filesystem use on windows. Fixes #5055.


[SVN r68115]

tools/quickbook

@@ -1 +1 @@
-Subproject commit b7fc6ccb05330a0f1a8a729cb6a107fc37b28a4d
+Subproject commit 6d7475344de4c04955164437f6d024a1827f01d2