U453 and buglist item - travel command updates

I wrote to the devteam early last week:
> Given my understanding of travel, it's supposed to be somewhat intelligent,
> and "convenient", and should, therefore avoid walking into water, lava,
> traps, or other things that distant movement would avoid, even if you're
> right next it.  Unless...  the travel destination is the "bad" location
> next to you when the travel starts.
To that end...
- add a context (iflags in 3.4.3 to maintain savefile compat) flag to
differenciate the first travel step from later steps, to allow the
detection of the final sentence, above.
- several changes to set/reset the travel1 flag as needed
- add code to findtravelpath to treat the first step specially if it's
the only step, allowing forced travel into a "bad" location
- correct the "don't travel over traps" code, which was getting confused
because hero's starting location was being avoided
- add code to avoid traveling into water and lava, duplicating
checks used for non-travel running
- fix some strange "guess" travel behavior: avoid zigzag paths when there's
a more direct path (even though the number of moves is the same)
- trunk change adds a new DISP_ALL tmp_at type, and uses it in some debug
code for travel, debug changes not added to the 3.4.3 branch

include/context.h

@@ -77,6 +77,7 @@ struct context_info {
 	long stethoscope_move;
 	short stethoscope_movement;
 	boolean  travel;	/* find way automatically to u.tx,u.ty */
+	boolean  travel1;	/* first travel step */
 	boolean  forcefight;
 	boolean  nopick;	/* do not pickup objects (as when running) */
 	boolean  made_amulet;

include/display.h

@@ -175,11 +175,12 @@
  * tmp_at() control calls.
  */
 #define DISP_BEAM    (-1)  /* Keep all glyphs showing & clean up at end. */
-#define DISP_FLASH   (-2)  /* Clean up each glyph before displaying new one. */
-#define DISP_ALWAYS  (-3)  /* Like flash, but still displayed if not visible. */
-#define DISP_CHANGE  (-4)  /* Change glyph. */
-#define DISP_END     (-5)  /* Clean up. */
-#define DISP_FREEMEM (-6)  /* Free all memory during exit only. */
+#define DISP_ALL     (-2)  /* Like beam, but still displayed if not visible. */
+#define DISP_FLASH   (-3)  /* Clean up each glyph before displaying new one. */
+#define DISP_ALWAYS  (-4)  /* Like flash, but still displayed if not visible. */
+#define DISP_CHANGE  (-5)  /* Change glyph. */
+#define DISP_END     (-6)  /* Clean up. */
+#define DISP_FREEMEM (-7)  /* Free all memory during exit only. */
 
 
 /* Total number of cmap indices in the sheild_static[] array. */