Three fixes for weapon trainers like Woo Ping:
1. Known weapon skills showed a "Create" button (calling castSpell on a
passive proficiency — no effect). Now only shows "Create" for actual
craft recipes where profDialog is non-zero; non-recipe known spells
fall through to the disabled "Train" button.
2. Added NPC gossip body text display. The gossip window now queries
CMSG_NPC_TEXT_QUERY and handles SMSG_NPC_TEXT_UPDATE to render the
NPC's text body (e.g. "Other weapon masters can teach...") above
the gossip options.
3. Fixed misleading TrainerSpell::state comment (was 0=unavailable,
1=available; actual WotLK convention is the reverse).
1bff4f7039