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
hubers: Add mass parameter for enforceEconservation

Add mass parameter for the enforcing of the energy conservation
with a neutral particle. needed for pi0 analysis. Further cleaning
up of the code.