Feature align - multiple peaks undefined behaviour

[xtrojak]

With #88, we unintentionally changed behaviour of feature.align. It concerns this part, that was changed to this part.

Basically, before in a loop a variable was always overwritten and the value from last iteration was taken. In new version, the usage of return statement in the for loop takes value from the first iteration. The tests did not discover this, probably because density function has mostly Gaussian shape with one peak, so it has no effect.