Undeterred by my previous bum patch, I'm sending more patches!

Most of these are "what do you think" patches.

1. Ensure-org-log-into-drawer-returns-nil-or-string

If the answer to my last question is "make sure `org-log-into-drawer'
never returns just t", then this patch does that. If that isn't the
answer, something can be done with `org-log-beginning'.

2. Missing-comma-in-org-agenda-with-point-at-orig-entry

The (currently unused) macro `org-agenda-with-point-at-orig-entry' is
missing a comma.

3. New-function-org-get-log-list and
New-function-org-agenda-show-log-item

This is the "what do you think part". The first patch finds and returns
the state log items of the current entry, as a list of parsed elements.
It probably doesn't try hard enough to make sure it's really found the
list.

The second implements an Agenda command which displays the text of the
most recent note on the entry under point. I use logging a lot, and am
forever looking at "WAIT" or "NEXT" todos, and wondering what the heck I
was waiting for, or actually supposed to do next.

If this is acceptable in principle, the finished product would probably
be a normal org-mode function, with an Agenda implementation on top of
that, and maybe some sort of guard against displaying overly-long notes.

Alternately, I could probably make this into something akin to
org-agenda-entry-text-mode, where *all* entries have their most recent
log item stuck under them. I find that sort of thing distracting, but
some people might like it.

WDYT?

Eric