Add new decfiles for Bu2JpsiK, Bu2etaK, Bu2SigmaL0barPPbar decays

This is related to MR 1314, 1319, 1386, and 1428, with same gen-level cuts on tracks & Lambda0 polarization config.

The B^+\to J/\psi K^+,~B^+\to \eta_c K^+ with J/\psi and \eta_c decay to \Sigma^0(\to \Lambda\gamma)pK, B^+\to \bar{\Sigma}^0p\bar{p}p decays are used to study the background of B^+\to \bar{\Lambda}phh analysis.

.dec files have been tested locally.

The included decays are listed here:

EventType	Decay
12105330	B+ -> (Sigma~0 -> (Lambda~0 -> p~- pi+) gamma) p+ p~- p+
12235002	B+ -> K+ (eta_c(2S) -> p+ (Lambda~0 -> p~- pi+) K-)
12135330	B+ -> K+ (J/psi(1S) -> p+ (Sigma~0 -> (Lambda~0 -> p~- pi+) gamma) K-)
12135331	B+ -> K+ (eta_c(1S) -> p+ (Sigma~0 -> (Lambda~0 -> p~- pi+) gamma) K-)
12135332	B+ -> K+ (eta_c(2S) -> p+ (Sigma~0 -> (Lambda~0 -> p~- pi+) gamma) K-)

cc @lsun.