IRR function args for tolerance and max iterations about pyxirr

[Anexen]

Thank you for submitting an issue.
I agree that there is a problem with the function being slow when there is no solution. This happens because several algorithms for finding roots are used internally. I'm working on the efficiency of finding roots to return None as soon as possible. I'm not sure that I can give the ability to control precision. As I wrote above, IRR uses several algorithms for finding roots and they use a different number of iterations and tolerance.

[Anexen]

Hi @Hvass-Labs,
I fixed an issue with IRR being slow when there is no solution in v0.9.3 + improved an overall performance. I didn't add the ability to control the precision, because IRR uses several root-finding algorithms and they use a different number of iterations and tolerance. I'll probably add the ability to select an algorithm instead of trying different options automatically.

[Hvass-Labs]

Thanks! I actually ended up making my own Cython version, but I appreciate your effort and I'm sure someone else will find it useful! :-)