0.8.0

The primary highlight of this research is the introduction of drudge scripts, which is a convenient and flexible domain-specific language for doing symbolic computations in drudge. This could make drudge a lot more convenient for simple tasks and more accessible for new comers, especially those unfamiliar with the Python language. Drudge scripts can be executed either by using exec_drs method of the Drudge class or using drudge as the main program.

Motivated by the drudge script, the tensor definitions are made more convenient to use even in the normal Python interface. Now tensor definitions subclasses the tensor class. So all arithmetic operations are automatically available. And they can be more conveniently created by the new Drudge.def_ method and added to the name archive by the Drudge.set_name method.

Also the LaTeX formatting has been improved with the option to suppress summations and the capability of using the LaTeX breqn package to automatically format long terms with a lot of factors. Also the LaTeX printing of tensors whose base is parsed by SymPy to have a subscript is fixed. Previously we get double subscripts for a base, which crashes both the original TeX and MathJAX.