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.

tests/test_column_extract.cpp

@@ -13,6 +13,7 @@
 #include <opm/core/io/eclipse/EclipseGridParser.hpp>
 
 #include <cstddef>
+#include <iostream>
 
 BOOST_AUTO_TEST_CASE(SingleColumnTest)
 {