Logger: remove an unnecessary include.

This'll stop Clang-Tidy's complaining that "default values in
virtual/override methods are prohibited". Dunno how prohibited they
are, but better safe than sorry, even though there was no compile
error/warning.

src/Application/Application.h

@@ -63,7 +63,7 @@ class Application: public Platform::Sdl2Application, public efsw::FileWatchListe
                               const std::string& dir,
                               const std::string& filename,
                               efsw::Action action,
-                              std::string old_filename = "") override;
+                              std::string old_filename) override;
 
     private:
         // Events

src/Logger/Logger.h

@@ -16,8 +16,6 @@
 // You should have received a copy of the GNU General Public License
 // along with this program.  If not, see <https://www.gnu.org/licenses/>.
 
-#include <ctime>
-
 #ifndef SAVETOOL_DEBUG_BUILD
 #include <fstream>
 #endif