NO-JIRA: Doxygen documentation improvements

- Added lots of doxygen comments.
- Replace doxygen-wrapper.sh with portable python script.
- Common configuration file for generating user and dev doxygen.
- Enable JAVADOC_AUTOBRIEF: no need for @brief.
- Use @ consistently for doc tags instead of mixing @ and \
- added tests/config_build.sh.in: make it easy to run tests against the build
- minor updates to system_tests_broker.py

git-svn-id: https://svn.apache.org/repos/asf/qpid/dispatch/trunk@1592808 13f79535-47bb-0310-9956-ffa450edef68