[Orgmode] FR: pre-select applicable templates depending on the context

[Bastien]

I have a few templates in `org-remember-templates': one that I mainly
use when I'm in my mailbox, another one that I mainly use when I'm
coding, one that I mainly use when I'm reading the web, etc.

I think it would make sense to reduce the number of available templates
when calling `org-remember'. This would be done by adding a new element
to each template:

            t: force pre-selection of this template in every context
'(major-mode): pre-select this template only in major mode (actually a
               list of major modes)
          nil: never pre-select this template, unless there are no other
               pre-selected templates

The default value would be `nil' for all template, so that the current
behavior wouldn't be touched.

Would people find this useful?

-- 
Bastien