Issue #11 + initFromLPFile is back, but will only works if the associated SBML file has been used before (Expected workflow : open a metabolic network from a SBML formatted source + write the associated LP model in a file + Open this model thanks to initFromLPFile) + during initialization of FBAProblem, fluxList and exchangeFluxList are initialized to NULL pointer + in the destructor of FBAProblem, fluxList and exchangeFluxList will be deleted if not null pointers + add one test corresponding to the new expected workflow (fbcSolveFromSBMLandLPFile) and a test to check that opening of LP_file alone is not allowed(fbcSolveFromLPFile). WARNING : no test is done in initFromLPFile to check that the LPfile furnished corresponds to the formerly loaded SBML metabolic network. This choice to give a sense of responsability to the users was done to avoid a loss of computing time performance