This softens dependency to activate more objects even in case of failed
activities. The downside is that 'activity_count' can't be used to limit the
number of processing nodes.

- reduce probability and cost of ConflictError by posting the
  activity result by activity
- do not post None (to force it, it's still possible to forge an
  ActiveResult object containing the None value)
- allow grouped messages to post results (previous implementation was not
  working, and this required to change the API of grouping methods)

More changes should be done so that Activity Tool provides an API to activate
an object using only its path.

It defaults to .01 and must be in the interval ]0, 1]
If a message expands to N objects, then it costs N / group_method_cost
and activity tool stop reserving messages the sum of all costs exceeds 1.

By default, this preserves original behaviour, i.e. MAX_GROUPED_OBJECTS = 100

Value 1 is not rejected to allow generic coding
(ex: activity_kw['group_method_cost'] = 1. / packet_size)

Tester accessors was not generated for acquired properties,
only content accessor was generated.

Extend test to prove the fix.

This Configurator Item was a Legacy which has no importance anymore, as
Business Template is not exported and installed on third party Instances
during the configuration.

The change from ocropus to tesseract as the conversor application
responsable  to convert image to text, made this tinny difference
between the outputs.

The difference was manually tested by Rafael to verify that it was caused
by the change of conversor application.

The Telephone is always presented using "+(0)" format, this is a feature
and expected behaviour.

is set or will be set later (through a Credential Recovery).