added convenient script for ctags generation
additional apis, fixed return type for stream decoding callback
big header-rearchitecting commit

archive-format:
  + removed redundant items from features enumeration
  + removed consts from aie_ArcFormat to be able to shoot myself
    in the foot
  + inlined accessors
archive-kinds:
  + renamed aie_ARC_KIND_MAX to aie_ARC_KIND_COUNT
archive:
  + written description commentrs where they were missing
util:
  + moved error handling away from util
  + added helper for free()
error:
  + new module with basic errno-like error handling