Dopey2

Results 2 issues of Dopey2

Hello, The permutation function doesn't work if the parameter **size** is higher than the length of the parameter **arr**. Example **Works** ```js G.permutation(['0', '1', '2', '3'], 4); ```` **Doesn't work**...

It is possible to load custom extensions such as http://docs.mathjax.org/en/latest/input/tex/extensions/cancel.html ?