Changed content model of <inherit> to require an explicit <type>

element, optionally contain a <purpose>, and make "access" attribute
implied.


[SVN r18152]

tools/boostbook

@@ -1 +1 @@
-Subproject commit 88a6031f3e08067a30b7edab6baf80275c3ab9f9
+Subproject commit 7f34f3e2e360a19d13b05cca6b637dc5700898d1