if Enge function is reversed (yields 0 for small z instead of 1) then correct it instead of throwing an exception

automatically count the number of particles in a FromFile distribution and throw an exception if it isn't equal to the number in the first line

Matched gauss fixes

Closes #234

See merge request !43

I added the sorting of the Eigenvectors in SigmaGenerator.h. I also implemented the renormalization method to ensure numerical consistence in Distribution.cpp. The code is working now, althought I dont know if the permutation plays a role in the matched distribution that is calculated