G_SHEOL & G_SHEOLONLY -> G_SHEOL & G_NOSHEOL

also. rndmonnum will no longer produce in Sheol mosters with G_NOSHEOL (or without G_SHEOL under old system)
allow vorpal jabberwock in Sheol

normal one appears, why not beheading one?
remove frequency from Aphrodite
Set cobra color to black (to distinguish blue cobra from blue pit viper)
remove G_NOSHEOL from snow ant and quantum mechanic

they also fit
Rodney distinguishable from Elvenking (now bright magenta)
make brown d less crowded

wolfs are now gray, wargs black
set riders to bright magenta, now color for super-dangerous
make rabid rat green

this monster is significantly more dangerous than other brown r