Previous implementation had the client send only epoch-time-in-seconds
to be signed by the server. Now the client sends random data and
epoch-time to be signed by the server.
Also added std::mutex for each new std::deque. cSendPkts is left as a
TSLQueue because it needs to support fast removal from the middle of the
data structure (mainly because the queued packets per ConnectionData has
an imposed limit of packets to hold).
Renamed "mutex" to "conMapMutex" since it is mainly used to lock access
to the connection map.
Removed UDPC_client_initiate_connection_pk() as publickey whitelisting
replaces its functionality.
Added event system to lessen the use of the main mutex and instead use
thread safe data structures (TSLQueue). Also can enable and check events
during execution (connect, disconnect, good mode, bad mode).
Fixes and refactorings.
