Transpiler improvements

[mistasse]

For now, the transpiling process is a really simple one. Several enhancements could be performed, but I would like to focus on the important ones first. So here is a list of the ones I have in mind. I will eventually add what

• the transpiler just doesn't do anything for mapping OOP features.
• the transpiler doesn't do much about python specificities (dict.items(), range(), ...). They are complicated to integrate. Can redbaron provide inspiration for pattern matching and transpilation ?
• the python code to be transpiled is not really python code. Do something about it ?