U453 and buglist item - travel command updates

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