Clean up configure/build-process.

- assume C++ standard-conforming environment
- add a user-option for gnuplot-support
- separate gnuplot-code into declaration and implementation,
  so we can define at EO-build-time whether to use it or not.

Adopt code and Makefiles to above changes.

Some minor fixes.

eo/src/utils/eoGnuplot1DSnapshot.cpp

@@ -0,0 +1,30 @@
+#ifdef HAVE_CONFIG_H
+#include <config.h>
+#endif
+
+#include "eoGnuplot1DSnapshot.h"
+
+
+
+inline eoMonitor&   eoGnuplot1DSnapshot::operator() (void)
+{
+  // update file using the eoFileMonitor method
+  eoFileSnapshot::operator()();
+
+  // sends plot order to gnuplot
+  //std::string buff; // need local memory
+  std::ostringstream os;
+  os << "set title 'Gen. " << getCounter() << "'; plot '"
+    // mk: had to use getFilename().c_str(), because it seems the string(stream) lib is screwed in gcc3.2
+      << getFileName().c_str() << "' notitle with points ps " << pointSize;
+  os << std::endl;
+  PipeComSend( gpCom, os.str().c_str());
+  return (*this);
+}
+
+
+
+// Local Variables:
+// c-file-style: "Stroustrup"
+// fill-column: 80
+// End: