Fixes in floating dates with migrated histories.

All service messages are now not multiline (including pinned).
Confirmation for profile photo deleting will be added (not enabled).
Copy-by-selection should be supported in Linux version now.
Drafts that contain only reply-to-id (without text) support added.

Telegram/SourceFiles/app.h

@@ -205,6 +205,7 @@ namespace App {
 	HistoryItem *contextItem();
 	void mousedItem(HistoryItem *item);
 	HistoryItem *mousedItem();
+	void clearMousedItems();
 
 	const style::font &monofont();
 	const QPixmap &sprite();