[Orgmode] making org-time-stamp a bit more interactive

[Adam Spiers]

If I have an existing time stamp (e.g. SCHEDULED/DEADLINE)
corresponding to (say) several months ago, and I want to update it to
some date in the future, but I want to see the calendar in order to
help decide the new date, I find the org-time-stamp interface slightly
lacking.  Ideally I could:

  - hit C-c . to start editing the time stamp
  - hit '.' to change it to the current day
  - use all the standard time stamp navigation bindings to move
    from today to a new date

Unfortunately the 2nd step does not update the Calendar buffer, so the
3rd step navigates relative to the original date, not relative to
today.  Would it be easy to fix this?  Ideally the fix would also
apply if the 2nd step involved typing something like '+2w'.

Thanks,
Adam