Change e-mail address of Michael Mayer
Create instance of log10(source energy) before passing the value to the cta_nedisp_kern constructor.

Before, the result of srcEng.log10TeV() was directly passed to the cta_nedisp_kern constructor, which stores only a reference to the value instead of the value. Since srcEng.log10TeV() does not return a reference but a value, it is not assured that the actual memory cell containing the value is still valid. This led to problems on CentOS 7.

Now, a local copy is created.

In the future we may avoid storing references and store directly the values. This should result in a negligible overhead, as the actual eval() method is called multiple times. We may still store references for large objects, but at least for simple arguments we should store by value.