Asset: Use references in the constructor

Author: adazem009

include/scratchcpp/asset.h

@@ -16,7 +16,7 @@ class AssetPrivate;
 class LIBSCRATCHCPP_EXPORT Asset
 {
     public:
-        Asset(std::string name, std::string id, std::string format);
+        Asset(const std::string &name, const std::string &id, const std::string &format);
 
         const std::string &assetId() const;
 

src/scratch/asset.cpp

@@ -7,7 +7,7 @@
 using namespace libscratchcpp;
 
 /*! Constructs Asset. */
-Asset::Asset(std::string name, std::string id, std::string format) :
+Asset::Asset(const std::string &name, const std::string &id, const std::string &format) :
     impl(spimpl::make_impl<AssetPrivate>(name, id, format))
 {
 }