2 new Unit-Tests for verifying the TCP checksum (T101, T102)
Implement connect and accept (but not tested yet)
Logging
Merge branch 'master' of https://github.com/HerbertBodner/cn.git

Conflicts:
	cn/src/nl/vu/cs/cn/TCP.java
	cn/src/nl/vu/cs/cn/TcpControlBlock.java
	cntest/src/nl/vu/cs/cn/test/TcpPacketTest.java