Remove obsoleted TcpInput

StreamInput based TcpInput is obsoleted since 2+ years ago.
So we can remove this class for newer plugin
Add udp input plugin
Add tcp input plugin
in_syslog uses socket utility handlers instead of own handlers
Remove trailing delimiter on both udp and tcp
Add other format tests to udp and tcp inputs
Merge pull request #368 from fluent/add-udp-tcp-input

Add udp and tcp input