add #include "../problem.h" into isolver.h
add #include "../problem.h" into isolver.h

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