DCCP: Modernize packet parsing

DCCP: Modernize packet parsing

Enable ND_LONGJMP_FROM_TCHECK.
Use ND_ICHECK*() for length checks.
Fix some length checks.
Add and use standard "invalid" sections.
Remove the redundant ND_TCHECK*() instances.
Add a ND_TCHECK_1().
Factorize some codes.
Update default format for tok2str() calls.
Indicate better invalid packet types, invalid option types,
invalid reset codes and invalid features.
Fix process for DCCP_OPTION_CHANGE_L/DCCP_OPTION_CHANGE_R, not the
same that DCCP_OPTION_CONFIRM_L/DCCP_OPTION_CONFIRM_R process.
Remove spaces in some dccp_feature_num_str[] strings.
Update the output of a test accordingly.