tty: hide cursor unless waiting for user input

Use vi (cursor_invisible) and ve (cursor_normal) to hide and show
cursor, if the terminal supports those.  This way on a slower
connection the cursor doesn't jump all over the place when doing
map or menu updates.

doc/fixes3-7-0.txt

@@ -2210,6 +2210,7 @@ tty: add support for petattr
 tty: if a ^C interrupt occurred while DECgraphics characters were being drawn
 	on the map, the "Really quit?" prompt would be illegible due to being
 	rendered with VT line drawing characters
+tty: hide cursor unless waiting for user input
 Unix: when user name is used as default character name, keep hyphenated value
 	intact instead stripping off dash and whatever follows as if that
 	specified role/race/&c (worked once upon a time; broken since 3.3.0)