Streamlined Beam neuronal network calculation.

Move NNoly parametrization from global variable to funtion. Results
are now the beam energy and the beamLV.
hubers: Add funtion to calculate scattering angle theta.

Add funtion to calculate the scattering angle theta between two
TLorentzVectors.
hubers: Add theta dependend Z cut.

Add theta dependend Z cut to hubers user functions.
Necessary for thin targets and "bad" vertex resolution.
hubers: Add bad spillist funtion.

Add function giving 1 if the current event is in a bad spill read
from a file. Could go to cuts.
hubers: Add function to shift two std::vectors.

Add function to shift two std::vectors by respective constant values.
Used to re-align the calorimeter.
hubers: Add funtion to generate neutral LV.

Add funtion to generate photon LV from coordinates of cluster and PV
and the cluster energy.
hubers: Add function to scale calorimeter cluster.

Add funtion to scale calorimeter cluster. In case of MC a linear energy
dependence is used. In case of RD a more complex energy and position
dependence is used. Calibrated for 2009 Primakoff data.
hubers: Add function to clean clusters.

Add function to clean clusters by filtering track association and time.
Clusters around the maximum cluster are merged into it depending on the
specified merge distance. Neccesar due to artificial cluster splitting
mainly in MC.
hubers: Add function to get maximum cluster.

Add function to get maximum cluster from std::vectors.
hubers: Add function to generate a form factor cut.

Add function to generate form factor correction. Currently hardcoded
for Nickel. Could go to cuts. SOme cleaning up of the code.
first attempt of implementing bgt track cut
Add pi0 to the constants.

Add neutralPionMass() to constants.
start implementing closest pi0 function