max HP manipulation

Life-saving has been setting u.uhpmax to max(2 * u.ulevel, 10)
and if it took place during level drain that could make u.uhpmax
increase instead of decrease, confusing healing which gets applied
to a monster who has drained the hero with Stormbringer or the
Staff of Aesculapius.  Change the setting to be max(u.ulevel, 10)
(removing the times two part) and also have level drain force it
to be set back to previous value if/when it gets increased.

Max HP loss due to strength trying to drop below 3 or to fire trap
or to being hit by Death now uses a mininum max HP of u.ulevel
rather than 1.  They don't have the alternate minimum of 10; I'm
uneasy that there are still two different minimum values.

I changed adjattrib() to set the flag to request a status update
before it gave its optional message rather than after so that the
new characteristic value would be visible during the message.  That
resulted in not updating status when eating royal jelly changed HP
or max HP after boosting strength.  But the same missing update
would have occurred--or rather, failed to occur--without the change
in sequencing if the strength boost causes a change in encumbrance.

include/extern.h

@@ -127,6 +127,8 @@ extern void init_attr(int);
 extern void redist_attr(void);
 extern void adjabil(int, int);
 extern int newhp(void);
+extern int minuhpmax(int);
+extern void setuhpmax(int);
 extern schar acurr(int);
 extern schar acurrstr(void);
 extern boolean extremeattr(int);