Some defaults chanigng in the mmenu conf--

Some defaults chanigng in the mmenu conf--
-- default to preload icons -- its fast, and doesn't slow user down later; they can set to defer themselves
-- default to unthreaded preview loads; better to hit the user now, than chug them for a few motions
-- show hourglass art while loading previews in foreground, so they know to wait
-- show previews after 2s or so, rather than 1s, of paused selection; give the user a bit more breather
--> this should all make the experience feel better

Preview caching--
-- if do_cache is set in conf, will now attempt to cache previews _to SD_ for long term storage
--> risk is the preview pics change, and mmenu never updates them; should maybe check preview pic
	age and re-export it once a month or something, or if age < pmnd age, or something.
-- Seledct menu can do 'mass cache', which chugs for a few mins, but will do all preview caching
-- otherwise, with do_Cache on (default!), after the 2s wait, it'll cache out to SD and load preview
--> thus, first preview is slow, but very fast next time, even next mmenu session