T S1: improved and cleaned up hp state tracking

We use a lua event on side 1 turn and attack end to update the relevant vars
This keeps all of the stat tracking in one place and reduces the number of vars used
T S1: do not cutoff student's moves once they move to Delf
T S1: improved text
T S1: greatly simplified Delf's lines about attacking
T S1: tweaked a line on zookeeper's request
T S1: used [message] speaker= syntax instead of [message] id= where applicable
T S1: show the wesnoth icon on 'lesson' messages
T S1: reduce occurrences of CONTINUE_MESSAGE
T S1: removed one further case of CONTINUE_MESSAGE
T S1: clear description_num on victory
T S1: fixup 6cf655b07b0a, I forgot the victory message
T S1: fixed indent on the lua block
T S1: purged a space in a message
T S1: clarified 'the ranged attack'
T S1: assign the 'veteran' role to any units who advance instead of flagging a var on them
T S1: removed defeat condition if player reaches turn 12 with the original quintain still alive

This includes a dialog to signal the time over victory, now default, and a dialog by Delf
on turn 9, if the quintain is still around urging the player to get to it. This contingency might be
encountered by an overly cautious player, or someone just dawdling
T S1: 'go up a level' -> 'gain a level'
T S1: more map updates
T S1: got rid of non-standard word wrap. In one case, split message into two messages
T S1: expand village capture SLF to all villages for portability