add low level first principle variables

add low level first principle variables:

cos_theta_yy_cm_bbyy phi_yy_cm_bbyy

Photon1_cos_theta_cm_gamgam Photon1_phi_cm_gamgam

HbbCandidate_Jet1_cos_theta_cm_bb HbbCandidate_Jet1_phi_cm_bb

DeltaPhi_bb_yy_cm_bbyy

(and keeping conventions of prefixes/suffixes used in the framework)