Massively change coding style in C++HL, using CamelCase for classes,
and restructuring namespaces; seasoned with functional changes in the
same commit for greater `svn blame` notoriety.

Item: Namespace changed from: subversion::cxxhl::version_1_9_dev
                          to: apache::subversion::
      Rationale: Namespace-based versioning doesn't really work in C ++.

Item: All class names changed from this_format to ThisFormat.
      Rationale: Easier to distinguish between classes and functions/methods.

Item: Namespace alias svn:: renamed to SVN::
      Rationale: Looks better with CamelCase class names.

Item: Imported weak_ptr<> and enable_shared_from_this into the compat namespace.
      Rationale: More smart pointer sanity.

Functional changes:
* subversion/bindings/cxxhl/src/exception.cpp (Error::throw_svn_error):
   Throw a Cancelled exception if SVN_ERR_CANCELLED appears anywhere in
   the error stack, not just at the top (because, realistically, it's
   more likely to be at the bottom of the stack).
 (<anonymous>::handle_one_error): Show symbolic error names in debug mode.

* subversion/bindings/cxxhl/tests/test_exception.cpp: Adjust the tests
   for the changed cancellation signalling semantics and compare trace
   output with the results of svn_handle_error2.


git-svn-id: https://svn.apache.org/repos/asf/subversion/trunk@1491748 13f79535-47bb-0310-9956-ffa450edef68