zmq: Annuary is now thread-safe to avoid data corruption when used by multiple threads
refactor: move dispatcher logic into a Dispatcher class
Handlers are now template class parameterized by their Worker (less code duplication)
Workers now inherit from a base class Worker from which they only override a virtual method
cppcheck: minor fixes
Annuary: use boost.foreach instead of hand-made loop (more readable and less error-prone)
refactor: SeD

* use boost::function instead of function pointers for callbacks.
It brings more flexibility, since we could now use functors or
even function with slightly different signature using boost::bind
* simplify heartbeat callback and its registration
ù*simplfiy SeD::getServices to use std::transform instead of hand-made loop