cmod: 3dstocmod: Create logger

Without creating a logger, the command dies with SEGFAULT when
Read3DSFile(std::istream&) tries to print the verbose message.

    GetLogger()->verbose("3DS file, {} bytes\n", chunkSize + 6);

Signed-off-by: Yasushi SHOJI <yashi@spacecubics.com>

src/tools/cmod/3dstocmod/3dstocmod.cpp

@@ -15,11 +15,13 @@
 
 #include <cel3ds/3dsread.h>
 #include <celmath/mathlib.h>
+#include <celutil/logger.h>
 
 #include "cmodops.h"
 #include "convert3ds.h"
 #include "pathmanager.h"
 
+using celestia::util::CreateLogger;
 
 void usage()
 {
@@ -35,6 +37,8 @@ int main(int argc, char* argv[])
         return 1;
     }
 
+    CreateLogger();
+
     std::string inputFileName = argv[1];
 
     std::cerr << "Reading...\n";