Improve multitasking during reflow

[GoogleCodeExporter]

Throw some EventAvail()s into the reflow loop so we're not totally locking up 
the machine if we're just slow to render a page.

This is pretty easy and we should have in 9.2.1 so we can tune it if needed for 
9.2.2 (and the new layout in 9.3).

Original issue reported on code.google.com by classi...@floodgap.com on 16 Jul 2010 at 3:08

• Blocked on: #1

[GoogleCodeExporter]

EventAvail()s tossed around where we look for Cmd-Period. While this doesn't 
allow the app to be backgrounded -- it will hang then if it was going to hang 
-- a stress test with MacSSH pointed to chargen showed that it was keeping up 
pretty well waiting for layout abort.

There is probably more we can do with this but this is good enough to make 
9.2.1.

Original comment by classi...@floodgap.com on 22 Jul 2010 at 3:54

• Added labels: Priority-Medium
• Removed labels: Priority-Critical

[GoogleCodeExporter]

Backed out. Too much overhead for pages like RetroMacCast -- on Classic it 
really chugs and even on the 1.8 adds about 20% overhead, even with 
conservative placement. I'll reconsider this after issue 1.

Original comment by classi...@floodgap.com on 17 Aug 2010 at 2:47