fix field::recover(), field::damage()

[salix5]

Problem

1. The ATK, DEF are int32, but the max of damage is 0xffff.

2. The recover may cause overflow.

Solution

1. Now amount is put in arg3, and it is int32.

2. Now the recover is capped at

   int32 limit = INT32_MAX - player[playerid].lp;

   If amount > limit, the system will:

   • recover limit LP
   • raise the event EVENT_RECOVER with amount