Initial import of MVA-based B->K*mumu line

MVA-based HLT2 line for B->K*mumu.

For muons, kaons, pions, dimuon, K* rdbuilder_thor definitions are used

Ideally Kstar and dimuon builders will use MVA selections but currently it isn't possible to use the CHILD functor for MVA input variables

B builder uses MVA selection, may add isolation variables as inputs if this becomes possible with ThOr functors, and may also add outputs of dimuon/K* MVA as input variables (requires CHILD functor)

The MVA selection seems to work with the TMVA.h file (Rec!2588 (merged)) - this will be needed for testing, as well as lhcb-datapkg/ParamFiles!37 (closed) for the weights file.