Fix wielded potions of blindness conferring resist

Without this fix, wielding a potion of blindness in the main or
alternate weapon slot would grant resistance to certain sources of
blindness, e.g. exploding yellow lights and archon gazes.

Reported with fix by arxanas, confirmed by ais523 and ishanyx:

    http://nethackwiki.com/wiki/Bugs_in_NetHack_3.4.3/Reports#Wielding_potions_of_blindness_confers_blindness_resistance

According to bcode, potions of blindness are the only object in the game
with oc_oprop == BLINDED, strangely enough.
Fix sight-blocking geno'd mimics not unblocking

Without this fix, giant mimics that take forms that block line-of-sight
(e.g. boulders, closed doors) will continue to do so even after being
genocided.

The easiest way to test this is in wizard mode: level teleport to a lit
version of Big Room, create a dozen giant mimics (some will look like
boulders) then wish for and read a scroll of genocide.  The points the
boulder-looking mimics occupied will still block sight to monsters,
which is very obvious with the dark_room patch.

This bug also exists in vanilla NetHack.
Fix giant turtles blocking sight after genocide

Without this fix, giant turtles will continue to block line of sight
even after being genocided.

This is meant to go with commit 6f979edc1b (CS565 add giant turtle) and
commit bfe41f9d6b (fix sight-blocking geno'd mimics not unblocking).

This bug also exists in UnNetHack.
Level genocide treats chameleons like normal geno

Normal dungeon-wide genocide treats chameleons as follows:

 1. Genociding the chameleon's true form kills it, no matter what form
    it happens to be at the time.
 2. Genociding the chameleon's current form forces it to change its
    form.

UnNetHack's new behavior for uncursed scrolls of genocide kills all of a
single monster from a level.  However, it treats chameleons differently:

 1. Genociding the chameleon's true form does nothing.
 2. Genociding the chameleon's current form kills it outright.

This commit fixes level genocide to work like dungeon-wide genocide on
chameleons/shape changers, which seems to be what was intended, and
makes it much more useful on e.g. the chameleons on the Rogue home
level.

For reference, mtmp->mnum is the true monster index (i.e. 'chameleon'
for chameleons), monsndx(mtmp->data) get's the monster's current form
(i.e. whatever the chameleon's form is at the time) and mtmp->cham is
set to a non-zero value when a shape changer takes on a form (1 for
chameleon, 2 for doppelganger, 3 for sandestin and 0 when not a shape
changer or a shape changer in their natural form).

This is meant to go with commit af6597c420 (CS122,126,230 nerf scrolls
of genocide).

This bug also exists in UnNetHack.
Fix Rogue level viewed from dungeon overview

Without this fix, choosing to view the Rogue level from the dungeon
overview while not on it will cause it to be displayed without its
'classic' Rogue graphics.  This would also affect future tiles ports if
different tile sets were used for Gehennom, the Gnomish Mines and other
areas.

This is meant to go with commit c461257372 (add remote dungeon level
viewing from the overview menu).

This bug also exists in upstream NitroHack.
Don't show autoexplore messages when just running

This suppresses autoexplore messages like "A boulder blocks your way"
when running after autoexplore encounters a boulder.

This bug also exists in NetHack4.
Stop autoexplore stopping for unrevealed mimics...

... or monsters with no active attacks, but stop if the monster is
peaceful/tame but can't be known due to hallucination.  These changes
should prevent e.g. object mimics in stores stopping autoexplore, and
allows autoexplore to continue in the presence of the likes of fungi,
floating eyes and gas spores.

The old behavior of stopping autoexplore around hidden mimics is a bug.

This bug also exists in NetHack4.
Favor room spaces during autoexplore

This change causes autoexplore to favor room spaces over, say, corridors
and other places to a factor of 5 to 1.  This should somewhat reduce the
frequency of autoexplore zipping right through dark rooms.

This is meant to go with commit a06d1c831d (autoexplore: prefer
exploring items).
Autoexplore to and stop on stairs/dungeon features

Autoexplore will now lead the player to stairs, ladders and various
dungeon features (altars, thrones, sinks and fountains), and will stop
autoexploring when stepping on them for the first time.

This is meant to go with commit 621c5ffedd (CS747,748,765,768,815
autoexplore from NetHack4), commit a06d1c831d (CS906 autoexplore: prefer
exploring items) and probably other autoexplore-related changes.