Upgrade to libxml 2.9.2 and libxslt 1.1.28

third_party/libxslt/TODO

+                  ********
+                 *        *
+                 *  TODO  *
+                 *        *
+                  ********
+
+Lifetime of result Value Tree, make sure we keep pointers. Exslt
+handling of node set values is especially nasty in this respect,
+lots of potential mem leaks...
+
+Pattern tester:
+  -> try to optimize for ID scan and tests.
+
+Pattern scanner:
+  -> add error checks on all returns
+
+Sorting:
+  -> add lang and case-order
+  -> add foreign sorting functions (interfaces ?).
+
+                  ********
+                 *        *
+                 *  DONE  *
+                 *        *
+                  ********
+
+Design:
+  - should transforms for a given stylesheet be thread clean,
+    -> the precompilation now occur only at stylesheet processing
+       time (except the binding for named templates and extension
+       functions which need to be computed once at run-time).
+       Multiple threads should be able to reuse the same stylesheet
+       now.
+
+Embedding Stylesheets:
+  - example in 2.7 would force to validate, we do it by default now
+
+ID and Key support:
+  -> Done
+
+Extra functions:
+  -> document() should not be a problem since Result Tree Fragments are
+     implemented
+  => Done
+
+Templates:
+  -> check the built-in template rule for attributes
+  -> make sure @xxx matches are applied
+
+Contextual error reporting:
+  -> provide a couple of functions providing context analysis, not urgent
+
+Validity:
+  -> should we add validation by default ? Make this an option
+  -> redirrect validity errors
+  => done added a special parsing mode
+
+Import:
+  -> parse them
+  -> provide functions to circulate in the import tree of stylesheets
+  -> make sure we use the cascade wherever it's needed
+
+Extra functions:
+  -> make a separate module.
+  => done functions.[ch]
+
+Support Attribute value templates:
+  -> starts to be urgent. Design it in flexible ways but try to optimize
+     to handle most of it at the stylesheet parse time ...
+  => Done for the most part need to check all attributes in XSLT constructs
+     using them and use the dedicated readin function.
+  -> optimization by checking their existence at stylesheet parse time.
+  => done when building the preproc function
+
+Sorting:
+  -> add support for imbricated sorts
+  => done but not well tested.
+
+Separate util module:
+  -> macros, config, verbosity ?
+  => xsltutils.[ch]
+
+Support for disable-output-escaping="yes":
+  -> looks problematic, libxml has no support for anything like this,
+     and unless adding a new node type :-( or tweaking text node and
+     output routines this is gonna be messy ... must be handled at libxml
+     level.
+  => Done with a trick, text node name is different, requires > 2.2.11
+
+Pattern scanner:
+  -> compute priority
+  -> handle unions
+  -> support for mode
+  => done
+
+Pattern tester:
+  -> also put fast lookup for "text()", "comment()", "node()"
+     based patterns lists.
+  => done
+
+Support Attribute value templates:
+  -> namespace support for attribute value templates is not done, need
+     a small API redesign
+
+Doc:
+  - put a page at http://xmlsoft.org/XSLT/
+  - generate/transform the DocBook to HTML
+  - add HTML to package
+  - manpage and doc for xsltproc
+
+
+Error handling:
+  -> check the version stuff, design a separate module for error interfacing
+     and default handling, parsing vs. runtime, fatal / compat / warning,
+     and lack of optionnal features.
+  -> reports context
+
+ID and Key support:
+  -> done but namespace support in keys is not defined
+  -> make sure keys are recomputed on new document input
+
+Profiler:
+  -> added looks good enough
+  -> autocorrection of initial calibration loop