added make_network function to Triangulation as well as fixed some more stuff. Also added even more functionality to ta_solver. I think it would be a good idea to make only one library from these functions. Also defined an object that inherits the networkx DiGraph class. If this project is to be taken further it is probably a good idea to rewrite all funtions to use this class for better readability
added notebooks of work on embedded braess networks as well as tests on the inheritance from nx classes