Fixes to tool/aube

At very long times aube was dropping decimal places in the output
precision. This is fixed now to one more digit than needed from the dt
point of view.

tools/aube.cpp

@@ -101,6 +101,8 @@ int main(int ac, char* av[])
 	double to_time   = -1.0;
 	double seconds_to_extract_from_end = -1.0; // negative means disabled
 	NeuronID maxid = std::numeric_limits<NeuronID>::max();
+	// one more decimal than neede to show values are not rounded
+	int decimal_places = -std::log(dt)/std::log(10)+2; 
 
 	try {
 		po::options_description desc("Allowed options");
@@ -267,7 +269,10 @@ int main(int ac, char* av[])
  	if( !output_file_name.empty() ) {
 		write_to_stdout = false;
  		of.open( output_file_name.c_str(), std::ofstream::out );
+		of << std::fixed << std::setprecision(decimal_places);
 	}
+	// sets output format to right number of decimal places
+	std::cout << std::fixed << std::setprecision(decimal_places);
 
 	while ( true ) {
 		// find smallest time reference