mutt: increase read_inc from 1000 to 10000
mutt: increase read_inc from 1000 to 10000

Folder loads are much faster now, so we can back off the UI update
frequency even more. Given my folders with 50-60k messages, these now
open in < 1s, and so updating the UI 5-6 times in that second instead of
50-60 seems appropriate.

wincent/wincent,wincent/wincent,wincent/wincent,wincent/wincent,wincent/wincent,wincent/wincent,wincent/wincent,wincent/wincent