In addition to being more code, this date parser would
treat local times as local, but anything that wasn't a
local time would get parsed as gmt, due to a quirk of
how tm2sec used to work.
This moves the code to tmparse, and fixes timezone parsing
at the same time.
This patch makes 3 changes:
- It makes upas/fs send plumb messages when a message
changes in the background (eg, someone on another imap
connection opens a message and sets the read flag)
- It makes faces not complain when it gets one of these
new modify messages.
- It makes acme/Mail update the flags in the display
when it gets one of these messages.
