fix #24
fix #24

as proposed by hugandr the code of L-BFGS-B now handles the cases for
numerical unstable objectives (possible bug when gradient-diff
norm was to small)

blefaudeux/CppNumericalSolvers,jdumas/CppNumericalSolvers,jdumas/CppNumericalSolvers,spinicist/CppNumericalSolvers,blefaudeux/CppNumericalSolvers,spinicist/CppNumericalSolvers,Daiver/CppNumericalSolvers,blefaudeux/CppNumericalSolvers,Daiver/CppNumericalSolvers,jdumas/CppNumericalSolvers,spinicist/CppNumericalSolvers,PatWie/CppNumericalSolvers,Daiver/CppNumericalSolvers,jdumas/CppNumericalSolvers,spinicist/CppNumericalSolvers,Daiver/CppNumericalSolvers,blefaudeux/CppNumericalSolvers