Some suggestions for the next version

Hi, Kasper,
There days, I try to learn cadabra to help me to do computation, it is great and I like it. BUT I find there are some things could be done better :

1. If cadabra could implement substitute operation continuously like mathematica in following method

a\.a->b\.b->c\.c->d...
, cadabra will be easier to use. After all, most people use this function frequently;

3. Add usage of keyboard shortcuts;

4. Add functions trace(especially,for gamma matrix) and dagger( I have mentioned it at another place);

5. Perfect fucntion substitute or add a function can change a b ... c d.. to c d...a b... ;

6. Update this paper Tutorial and reference guide to 2.x;

7. Add optional parameter to make function keep original value unchangable after implementing(especially, function substitute);

8. Make notebook supports Chinese language when writing in latex mode.

I just wish cadabra would be more perfect.Thanks for your so great work again.