fix checksum
add ipv6 support in DSCP,ECN,IP_PROTO set_field
fix padding
fix oxm functions
add missing icmpv6 entry in constructing oxm sequence
Merge pull request #96 from iHiroakiKawai/checksum

fix checksum
Merge pull request #97 from iHiroakiKawai/ipv6_set_field

add ipv6 support in DSCP,ECN,IP_PROTO set_field
Merge pull request #98 from iHiroakiKawai/padding

fix padding
Merge pull request #99 from iHiroakiKawai/oxm_functions

fix oxm functions
Merge pull request #100 from iHiroakiKawai/icmpv6

add missing icmpv6 entry in constructing oxm sequence
fix warnings