use H_SEQ_INDEX to access a sequence
pull out struct types of complex rdata fields
move api additions to glue.[ch]
replace another field access with a glue macro
rewrite dns domain grammar using H_RULE
add an assertion to h_seq_index
move get_domain logic into an action on the domain parser
replace get_domain calls in set_rr with H_FIELD
replace remaining get_domain calls and remove get_domain
remove left-over definitions that have moved to glue.h
don't add _t type suffix inside H_ macros