[doc] fix camera vertical flip default doc

The property is already set to True in
src/morse/builder/sensor.py:397

Spotted by Ellon M.
[datastream] Allow to pass option configuration to stream manager

It introduces Environment::configure_stream_manager at the builder
level. Information is stored in component_config using the
stream_manager dictionnary, and then passed to the ctor of each
DataStream Manager.

Update the prototype of DatastreamManager.__init__ and its son to pass
these additional information
[core] Add an 'action' handler in datastream manager

Will help for hla implementation, and may be used for other purpose,
such as clock triggering.
See https://sympa.laas.fr/sympa/arc/morse-dev/2014-10/msg00018.html for
the beginning of the discussion.
[doc] Note the addition of configure_stream_manager and action handler
[doc] Update argument_passing to document stream_manager dictionnary

While here, update the generated code, which does not use anymore json,
but pprint (since 520605224)
[doc] Document that one may want to override DatastreamManager.action
[blender/main] Remove unused functions
[core] Replace datastreamDict by stream_managers

- Consistent with python style
- Define more clearly what it represents
- While here, fix some insane logic around it
- Update the associated documentation.
[middleware] Introduce stuff for HLA as a middleware

Provides an implementation for HLA as a standard Morse middleware.
It does not provide API for the whole HLA standard, but only:
  - time management (with some design issues)
  - objects attribute management
  - synchronisation point

Other possible interesting points to manage in the future is:
  - interactions mechanisms
  - region management

Provides also two examples, working with the CERTI Example fed Test.fed
[mw/hla] Deal properties with new stuff from master
[blender/main] Be more robust in case of exception in Datastream Manager creation
[builder] Add an entry for hla stream manager