Split plugin classes and derive AIFilePicker from BasicPluginBase (part 3).

This commit deletes all indra/media_plugins and copied one-on-one
the indra/plugins directory from my (imprudence) statemachine branch
(which contains the AIFilePicker patch).

git shows this as a lot of 'renamed' files because originally it
was a rename. However, there are a lot of changes as well: it's both
an upgrade to a newer plugin system (changes by LL) as well as an
upgrade to my refactored plugin system with a file picker as plugin.

Since this commit is a one-on-one copy, it disregards any changes
that were in Singularity and not in imprudence in indra/media_plugins
however. I will add those back in the next commit.

indra/plugins/base_basic/basic_plugin_base.h

@@ -0,0 +1,88 @@
+/** 
+ * @file basic_plugin_base.h
+ * @brief Basic plugin base class for Basic API plugin system
+ *
+ * @cond
+ * $LicenseInfo:firstyear=2010&license=viewergpl$
+ * 
+ * Copyright (c) 2010, Linden Research, Inc.
+ * 
+ * Second Life Viewer Source Code
+ * The source code in this file ("Source Code") is provided by Linden Lab
+ * to you under the terms of the GNU General Public License, version 2.0
+ * ("GPL"), unless you have obtained a separate licensing agreement
+ * ("Other License"), formally executed by you and Linden Lab.  Terms of
+ * the GPL can be found in doc/GPL-license.txt in this distribution, or
+ * online at http://secondlife.com/developers/opensource/gplv2
+ * 
+ * There are special exceptions to the terms and conditions of the GPL as
+ * it is applied to this Source Code. View the full text of the exception
+ * in the file doc/FLOSS-exception.txt in this software distribution, or
+ * online at
+ * http://secondlife.com/developers/opensource/flossexception
+ * 
+ * By copying, modifying or distributing this software, you acknowledge
+ * that you have read and understood your obligations described above,
+ * and agree to abide by those obligations.
+ * 
+ * ALL LINDEN LAB SOURCE CODE IS PROVIDED "AS IS." LINDEN LAB MAKES NO
+ * WARRANTIES, EXPRESS, IMPLIED OR OTHERWISE, REGARDING ITS ACCURACY,
+ * COMPLETENESS OR PERFORMANCE.
+ * $/LicenseInfo$
+ * 
+ * @endcond
+ */
+
+#ifndef BASIC_PLUGIN_BASE_H
+#define BASIC_PLUGIN_BASE_H
+
+#include <sstream>
+
+#include "linden_common.h"
+
+#include "llplugininstance.h"
+#include "llpluginmessage.h"
+#include "llpluginmessageclasses.h"
+
+class BasicPluginBase
+{
+public:
+	BasicPluginBase(LLPluginInstance::sendMessageFunction send_message_function, LLPluginInstance* plugin_instance);
+	//! Basic plugin destructor.
+	virtual ~BasicPluginBase() {}
+
+	//! Handle received message from plugin loader shell.
+	virtual void receiveMessage(char const* message_string) = 0;
+
+	// This function is actually called and then calls the member function above.
+	static void staticReceiveMessage(char const* message_string, BasicPluginBase** self_ptr);
+
+protected:
+	void sendMessage(LLPluginMessage const& message);
+
+	//! Message data being sent to plugin loader shell by mSendMessageFunction.
+	LLPluginInstance* mPluginInstance;
+
+	//! Function to send message from plugin to plugin loader shell.
+	LLPluginInstance::sendMessageFunction mSendMessageFunction;
+
+	//! Flag to delete plugin instance (self).
+	bool mDeleteMe;
+};
+
+/** The plugin <b>must</b> define this function to create its instance.
+ * It should look something like this: 
+ * @code
+ * {  
+ *    *plugin_object = new FooPluginBar(send_message_function, plugin_instance); 
+ *    return 0; 
+ * }  
+ * @endcode
+ */
+int create_plugin(
+	LLPluginInstance::sendMessageFunction send_message_function, 
+	LLPluginInstance* plugin_instance, 
+	BasicPluginBase** plugin_object);
+
+#endif // BASIC_PLUGIN_BASE
+