Fix few warnings noticed with x64 MSVC build

src/gfx/font.cpp

@@ -138,7 +138,7 @@ int Font::scanf(int x, int y, char *str, int max_len) {
 
     tausta_roska = new Bitmap(x, y, (width + 1) * (max_len + 1), height);
 
-    kohta = strlen(str);
+    kohta = (int)strlen(str);
 
     ch = 0;
 

src/settings.cpp

@@ -362,7 +362,7 @@ void load_roster(void) {
             struct rosteri_header hdr;
             int ret;
 
-            ret = fread(&hdr, sizeof(hdr), 1, faili);
+            ret = (int)fread(&hdr, sizeof(hdr), 1, faili);
             if (ret != 1) {
                 printf("failed to read roster.dta header\n");
                 exit(1);