Remove CPP code in favor of numba

[cbespin]

Browsing the code, I noticed usage of Cython functions for histogramming and array operations. Maybe those can be ported to numba to remove the cython/cpp dependency, making this project pure python.
If this is considered useful, I am willing to do a speed comparison and provide a PR when I find the time.

[leloup314]

Sounds nice to me ;) Maybe you have the time to look at the pylandau numba port (which is essential done) and check if this is fine? This uses AOT instead of a (probably) faster JIT approach

[cbespin]

Yes, I will (come time). The same can probably applied here, if it proves as an advantage.

[YannickDieter]

I like the idea. :)