Made String(char) explicit

Former-commit-id: 02f5ead8fe60b825464f956d9fc6ea4689bda44b

include/Nazara/Core/String.hpp

@@ -32,7 +32,7 @@ class NAZARA_API NzString : public NzHashable
 		struct SharedString;
 
 		NzString();
-		NzString(char character);
+		explicit NzString(char character);
 		NzString(const char* string);
 		NzString(const std::string& string);
 		NzString(const NzString& string);

include/Nazara/Math/Basic.inl

@@ -189,7 +189,7 @@ NzString NzNumberToString(long long number, nzUInt8 radix)
 	#endif
 
 	if (number == 0)
-		return '0';
+		return NzString('0');
 
 	static const char* symbols = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ";