implementation of RBA (resource balance analysis)

xbanalysis/model/xba_compartment.py

xbanalysis/model/xba_model.py

xbanalysis/model/xba_reaction.py

xbanalysis/model/xba_species.py

xbanalysis/problems/__init__.py

xbanalysis/problems/fba_problem.py

xbanalysis/problems/lp_problem.py

xbanalysis/problems/rba_problem.py

xbanalysis/utils/utils.py