make GCC 4.4 happy

there was a "typename" outside of a template, but because the
syntactic sugar is created by the Boost unit testing framework, it was
not clear wheter it was a template or not.

Also, some harmless warnings have been fixed. These only appeared
because a few variables have recently been converted from int to
size_t...

opm/parser/eclipse/IntegrationTests/BoxTest.cpp

@@ -28,6 +28,8 @@
 
 using namespace Opm;
 
+// forward declaration to avoid a pedantic compiler warning
+EclipseState makeState(const std::string& fileName);
 
 EclipseState makeState(const std::string& fileName) {
     ParserPtr parser(new Parser( ));