Update ChangeLog.
No boost linkage neccessary any more.

AgentXcpp programs do not longer need -lpthread and -lboost_system,
because boost:asio was already removed.
Updated ChangeLog.
Quickfix: Fix a tutorial.
Update README.
Quickfix: Wrong revision in docs sometimes.

When building the documentation without being in a git repo (e.g. from a
relase package), a wrong revision was inserted. Now, no revision is
inserted at all in such cases.
Remove check for boost::asio.
Add missing #include.
Fix thread synchronization problem.

The UnixDomainConnector::request() and UnixDomainConnector::do_receive()
functions were not well synchronized, which caused deadlocks.
Rename a mutex in UnixDomainConnector.
Fix namespace issue in helpers.cpp.