Replaced servlet and servlet mapping in web.xml with Servlet 3.0
annotation
Reverse the previous change - it was not supposed to be in the develop
branch
Sitemap allows for multiple redirects in getRedirectForxxx methods.
getRedirectForxxx methods renamed for consistency.
Fixed missing call to loadNodes() in
DefaultUserNavigationTree.loginStatusChange()

Fixed StandardPages - 'private', and therefore any of its children, was
not being displayed because it had no LabelKey.
SitemapChecker modified to ensure that a redirect target will not be
prevented from being visible by an ancestor having a missing label key

Changed 'permission' to 'role' (missed from earlier refactoring)

Changed DefaultRealm to use new page permission syntax of page:view:*

Corrected logic for loading nodes; login shown only when user not logged
in, logout never shown.  See #158, #157, #221  Testbench tests still required
Fixes #223
Test for authorisation failure.  Tests refactored to make login / logout
available in test case
Navigator is last to receive login status change.  Fixes #225
Added some browser back/forward tests.  All tests green
Added a couple of checkNotNulls to the Sitemap
Added authentication failure test
Closes #221