add hashing and operator== to Description

uvoscam.h

@@ -37,12 +37,23 @@ class Camera
 {
 public:
 	
-	struct Description
+	class Description
 	{
+	public:
 		std::string vendor;
 		std::string serial;
 		std::string id;
 		std::string model;
+		
+		size_t getHash() const
+		{
+			return std::hash<std::string>{}(vendor + serial + id + model);
+		}
+		
+		bool operator==(const Description& in) const
+		{
+			return in.getHash() == getHash();
+		}
 	};
 	
 	static constexpr size_t BUFFER_DEPTH = 8;