We continue to add (full python) experimental models. In 1.15, we introduce the CTBN model (Continuous Time Bayesian Network) featuring, as usual, modelization and representation, inference (exact and sampling) and a learned algorithm. * aGrUM * Added `gum::NodeId gum::EssentialGraph::idFromName(const std::string& name)` and `const std::string& gum::EssentialGraph::nameFromId(gum::NodeId node)`. * pyAgrum * Added `pyAgrum.EssentialGraph.idFromName(str)->int` and `pyAgrum.EssentialGraph.nameFromId(int)->str` * Improved documentation of `pyAgrum.lib.explain` * Better `pyAgrum.clg.CLG.toDot()` and `pyAgrum.clg.CLG._repr_html()`. * New model Continuous Time Bayesian Network `pyAgrum.ctbn`. * Formatted and adjustments in `pyAgrum.ctbn`. * Updated documentations for python experimental models notebooks. * Updated thumbnails for python experimental models notebooks. * Added serialization (pickle) for CLG and CTBN (consistent with other models in pyAgrum). * Improved `pyAgrum.lib.utils.{apply_}dot_layout` * Added `pyAgrum.lib.utils.async_html2image` for exported HTML as png or pdf (notably for `pyAgrum.lib.notebook.getSideBySide` and `pyAgrum.lib.notebook.getPotential`).