WIP: Pointwise Safe Exponential Function

Exponential overflows introduce an often times unnessecary source of run abortions into reconstructions. Especially in early reconstructions, when the position is still far from converged, stray samples tend to cause exponential overflows during the minimizations, if not mitigated.

I propose to add a 'safe' exponential function to the pointwise functions which surpesses exponential overflows. It does this by clipping input value to safe limits prior to applying the exponential function.