TypeError: object of type <class 'float'> cannot be safely interpreted as an integer.

Hi,

Nice application!

In "evaluator.py", lines 29 and 33 throw a numpy linspace error.
Casting fs/2 and fftlength/2 as int() solves the error for me (on windows, with python 3.8).

self.f = np.linspace(0,int(fs/2),int(fftlength/2 + 1)) * 60

