Solution: use msleep (SETTLE_TIME) everywhere when waiting for the
connections/sockets to be settled instead of a variety of patterns
and functions to make tests more coherent.
Tests were failing, because some deque calls were causing undefined
behavior: calling front() or pop_front() on an empty deque. Such
calls are now safeguarded.
Of course people still "can" distributed the sources under the
LGPLv3. However we provide COPYING.LESSER with additional grants.
Solution: specify these grants in the header of each source file.
