trunk only: preserving context (src files)

Pat Rankin wrote:
> collect them all into some new struct and
> save that separately rather than jamming more non-option stuff
> into struct flags.

This patch:
- collects all context/tracking related fields from flags
  into a new structure called "context."
It also adds the following to the new structure:
- stethoscope turn support
- victual support
- tin support

src/wizard.c

@@ -73,7 +73,7 @@ amulet()
 	    }
 	}
 
-	if (!flags.no_of_wizards)
+	if (!context.no_of_wizards)
 		return;
 	/* find Wizard, and wake him if necessary */
 	for(mtmp = fmon; mtmp; mtmp = mtmp->nmon)
@@ -260,7 +260,7 @@ strategy(mtmp)
 			break;
 	}
 
-	if(flags.made_amulet)
+	if(context.made_amulet)
 	    if((strat = target_on(M3_WANTSAMUL, mtmp)) != STRAT_NONE)
 		return(strat);
 
@@ -468,7 +468,7 @@ resurrect()
 	long elapsed;
 	const char *verb;
 
-	if (!flags.no_of_wizards) {
+	if (!context.no_of_wizards) {
 	    /* make a new Wizard */
 	    verb = "kill";
 	    mtmp = makemon(&mons[PM_WIZARD_OF_YENDOR], u.ux, u.uy, MM_NOWAIT);
@@ -537,7 +537,7 @@ intervene()
 void
 wizdead()
 {
-	flags.no_of_wizards--;
+	context.no_of_wizards--;
 	if (!u.uevent.udemigod) {
 		u.uevent.udemigod = TRUE;
 		u.udg_cnt = rn1(250, 50);