Fix typo in method name.
Rename method to an accurate name ('close' is misleading)
HORNETQ-1128 Improve schema documentation, add some intra-manual links
Add description to assertion in test.
HORNETQ-1148 Bump the version to fail properly if server is older:
Connecting from a 2.3-client (now, version 123) to a 2.2 server will fail due
to serialization errors. Better a `version incompatibility` error.
First close all sessions, THEN start waiting for completion.
Remove the setContext call, from server.stop() as the methods inside
ServerSession are already handling the context switching.

Also make the sessionContext 'final', it simplifies the code and we
can assume more about it
Merge pull request #898 from FranciscoBorges/stop-server-sessions

First close all sessions, THEN start waiting for completion.
Merge pull request #897 from FranciscoBorges/version-hq-1148

HORNETQ-1148 Bump the version to fail properly if server is older:
Merge pull request #896 from FranciscoBorges/schema

HORNETQ-1128 Improve schema documentation, add some intra-manual links