[PATCH 0 of 3] keyword: enhance docs for template (filters), ease testing

[Christian Ebert]

Hi,

As everybody is on vacation I might as well update ;-)

1. removes keyword help test, not really useful.

2. improves documentation for templates and filters,
   references "hg help templates".
 
   Or should it be 'hg help templates' when quoted in help?

3. saves an import by using util.datestr, and provides the
   utcdate filter in a public variable instead of a function.

Once "hg help templating" collects also templates/filters added
by extensions this might ease the task.

c