Restore size_t, make it limit, add size64

Because size() is used in many printf()s, we can't just change its return type to uint64. Instead, when size is > size-max, return size-max. Add size64 which can be used by new apps who care about >4GB cards.
esp8266 · earlephilhower · May 19, 2019 · May 14, 2019 · May 15, 2019 · May 15, 2019
commit b4d9834e7686e7733e8b145444b4be69e703f516
diff --git a/libraries/SD/src/SD.h b/libraries/SD/src/SD.h
@@ -115,7 +115,12 @@ class SDClass {
         return blocksPerCluster() * blockSize();
     }
 
-    uint64_t size() {
+    size_t size() {
+        uint64_t sz = size64();
+	return (size_t)std::min( (uint64_t)SIZE_MAX, sz );
+    }
+
+    uint64_t size64() {
         return ((uint64_t)clusterSize() * (uint64_t)totalClusters());
     }