add new subroutine to study bunch normality

Normality test has been already coded-up into ALaDyn. In ALaDyn we have
only implemented the Jarque-Brera (Urzula version) test. In order to
verify the null hypothesis a Python script has been set-up. This scrip
should perform different tests. So far only Shapiro seemed to work, but
the bunch dimension is too large and subsempling should be implemented.