Move heartbeat functionality into heartbeat.cc

Use STL containers for heartbeat implementation.
FAIL on valgrind error for DEVELOP build
Print warning on check_memory not being executed for testsuite.
cleaning heartbeats upon exit
fix heartbeat impl
Adding valgrind supprssion for libz
fix testsuite check_memory warning
restrict MUD_IP hack to CYGWIN only
proper implement flush_message
Adding telnet client tests.
Remove ThreadPool files as they are not in use.
Fix expect tests
Merge pull request #189 from sunyc/master

Revamp heartbeat implementation