ecxx: Dropped deprecated naming.

Basically, "s/eo3/ecxx/g".
ecxx: Fixed a bug in the generated code.

There was a hardcoded name amongst the eo_class_operation_generator
grammar definition.
ecxx: Converted all c-style casts to static_cast and removed unecessary casts.
ecxx: Fixed indentation.
ecxx: Added support to Eo-1 in eo_base.hh and eo_wref.hh.

eo_private.hh and inherit.hh still lack this support.
ecxx: Adding ECXX_USE_EO1 flag to compilation.
ecxx: Added module eo_version_generator.
ecxx: Added eolian example.