add constant value
- ofp_port_config
- ofp_port_features
- ofp_packet_in_reason
- ofp_flow_removed_reason
fix ipv4_* of packet_info
Fix an issue on creating DecIpTtl
Add simple_router for trema-edge.
fix indentation
added the --daemonize option to command-line of trema-switch
add sigterm handler
add -Werror to CFLAGS
add -Wno-error=sign-conversion to CFLAGS of libruby
fix compiler warnings
fix CFLAGS of libruby
add missing delete_list() after using list_element.

For memory leaks.
Merge branches 'trivial1' and 'trivial1' of https://github.com/iHiroakiKawai/trema-edge into trivial1