include iostream in the files which use std::cerr or std::cout

for some of these files this is needed to make to keep it compiling
after the next patch because the new ErrorMacros.hpp file will no
longer implicitly includes <iostream>. for the remaining files it is
just good style.

While at it, the includes for most of these files have been ordered in
order of decreasing abstraction level.

opm/core/linalg/LinearSolverIstl.cpp

@@ -40,6 +40,7 @@
 #include <dune/istl/paamg/kamg.hh>
 
 #include <stdexcept>
+#include <iostream>
 
 
 namespace Opm

opm/core/pressure/IncompTpfa.cpp

@@ -33,6 +33,7 @@
 #include <opm/core/utility/ErrorMacros.hpp>
 #include <opm/core/utility/miscUtilities.hpp>
 #include <opm/core/wells.h>
+#include <iostream>
 #include <iomanip>
 #include <cmath>
 #include <algorithm>

opm/core/props/rock/RockCompressibility.cpp

@@ -25,6 +25,8 @@
 #include <opm/core/utility/ErrorMacros.hpp>
 #include <opm/core/utility/linearInterpolation.hpp>
 
+#include <iostream>
+
 namespace Opm
 {
 

opm/core/props/satfunc/SaturationPropsFromDeck_impl.hpp

@@ -26,6 +26,8 @@
 #include <opm/core/props/phaseUsageFromDeck.hpp>
 #include <opm/core/grid.h>
 
+#include <iostream>
+
 namespace Opm
 {
 

opm/core/simulator/initState_impl.hpp

@@ -30,6 +30,8 @@
 #include <opm/core/props/IncompPropertiesInterface.hpp>
 #include <opm/core/props/BlackoilPropertiesInterface.hpp>
 #include <opm/core/props/phaseUsageFromDeck.hpp>
+
+#include <iostream>
 #include <cmath>
 
 namespace Opm

opm/core/tof/TofDiscGalReorder.cpp

@@ -28,9 +28,11 @@
 #include <opm/core/utility/VelocityInterpolation.hpp>
 #include <opm/core/utility/parameters/ParameterGroup.hpp>
 #include <opm/core/linalg/blas_lapack.h>
+
 #include <algorithm>
 #include <cmath>
 #include <numeric>
+#include <iostream>
 
 namespace Opm
 {

opm/core/tof/TofReorder.cpp

@@ -22,9 +22,11 @@
 #include <opm/core/grid.h>
 #include <opm/core/utility/ErrorMacros.hpp>
 #include <opm/core/utility/SparseTable.hpp>
+
 #include <algorithm>
 #include <numeric>
 #include <cmath>
+#include <iostream>
 
 namespace Opm
 {

opm/core/transport/reorder/ReorderSolverInterface.cpp

@@ -25,6 +25,7 @@
 
 #include <vector>
 #include <cassert>
+#include <iostream>
 
 
 void Opm::ReorderSolverInterface::reorderAndTransport(const UnstructuredGrid& grid, const double* darcyflux)

opm/core/transport/reorder/TransportSolverCompressibleTwophaseReorder.cpp

@@ -28,6 +28,7 @@
 #include <opm/core/utility/miscUtilitiesBlackoil.hpp>
 #include <opm/core/pressure/tpfa/trans_tpfa.h>
 
+#include <iostream>
 #include <fstream>
 #include <iterator>
 #include <numeric>

opm/core/transport/reorder/TransportSolverTwophaseReorder.cpp

@@ -27,6 +27,7 @@
 #include <opm/core/utility/miscUtilities.hpp>
 #include <opm/core/pressure/tpfa/trans_tpfa.h>
 
+#include <iostream>
 #include <fstream>
 #include <iterator>
 #include <numeric>

opm/core/utility/miscUtilities.cpp

@@ -26,6 +26,7 @@
 #include <opm/core/props/BlackoilPropertiesInterface.hpp>
 #include <opm/core/props/rock/RockCompressibility.hpp>
 #include <opm/core/utility/ErrorMacros.hpp>
+#include <iostream>
 #include <algorithm>
 #include <functional>
 #include <cmath>

opm/core/utility/miscUtilitiesBlackoil.cpp

@@ -27,6 +27,7 @@
 #include <opm/core/simulator/BlackoilState.hpp>
 #include <opm/core/simulator/WellState.hpp>
 #include <opm/core/utility/ErrorMacros.hpp>
+#include <iostream>
 #include <algorithm>
 #include <functional>
 #include <cmath>

opm/core/wells/WellsGroup.cpp

@@ -19,11 +19,13 @@
 
 #include "config.h"
 #include <opm/core/wells/WellsGroup.hpp>
-#include <cmath>
-#include <memory>
 #include <opm/core/wells.h>
 #include <opm/core/props/phaseUsageFromDeck.hpp>
 
+#include <cmath>
+#include <memory>
+#include <iostream>
+
 namespace Opm
 {
 

opm/core/wells/WellsManager.cpp

@@ -35,6 +35,7 @@
 #include <map>
 #include <string>
 #include <utility>
+#include <iostream>
 
 
 // Helper structs and functions for the implementation.