S3 bucket listing support and network code refactors.

* Adds support for listing all objects in an S3 bucket.
* Renames a bunch of network related classes (Download->Action)
* Net actions now have static constructors

logic/net/S3ListBucket.h

@@ -0,0 +1,42 @@
+#pragma once
+#include "NetAction.h"
+
+struct S3Object
+{
+	QString Key;
+	QString ETag;
+	qlonglong size;
+};
+
+typedef std::shared_ptr<class S3ListBucket> S3ListBucketPtr;
+class S3ListBucket : public NetAction
+{
+	Q_OBJECT
+public:
+	S3ListBucket(QUrl url);
+	static S3ListBucketPtr make(QUrl url)
+	{
+		return S3ListBucketPtr(new S3ListBucket(url));
+	}
+
+public:
+	QList<S3Object> objects;
+
+public
+slots:
+	virtual void start() override;
+
+protected
+slots:
+	virtual void downloadProgress(qint64 bytesReceived, qint64 bytesTotal) override;
+	virtual void downloadError(QNetworkReply::NetworkError error) override;
+	virtual void downloadFinished() override;
+	virtual void downloadReadyRead() override;
+
+private:
+	void processValidReply();
+
+private:
+	qint64 bytesSoFar = 0;
+	QString current_marker;
+};