Improved determining path & filename when saving/loading a save-state (#691) (PR #849)

Whenever harddisks/disks are inserted (or removed) and *if path has changed* then:
. Then the internal save-state's path & filename will be updated to reflect the new defaults.
. LoadConfiguration(): Read the save-state pathname from Registry before harddisks/disks.

Also:
. CiderPress: only save pathname on OK.
. Refactored CPropertySheetHelper::BrowseToFile().
. Extended support for -d1,-d2,-h1, etc such that if the param is "", then it will eject/unplug the disk/harddisk.

source/Disk2CardManager.cpp

@@ -132,3 +132,16 @@ bool Disk2CardManager::IsAnyFirmware13Sector(void)
 	}
 	return false;
 }
+
+void Disk2CardManager::GetFilenameAndPathForSaveState(std::string& filename, std::string& path)
+{
+	for (int i = NUM_SLOTS-1; i >= 0; i--)	// scan slots backwards: 7->0
+	{
+		if (GetCardMgr().QuerySlot(i) == CT_Disk2)
+		{
+			dynamic_cast<Disk2InterfaceCard&>(GetCardMgr().GetRef(i)).GetFilenameAndPathForSaveState(filename, path);
+			if (!filename.empty())
+				return;
+		}
+	}
+}