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/webkit/dummy_volume_catcher.cpp

@@ -0,0 +1,65 @@
+/** 
+ * @file dummy_volume_catcher.cpp
+ * @brief A null implementation of the "VolumeCatcher" class for platforms where it's not implemented yet.
+ *
+ * @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
+ */
+
+#include "volume_catcher.h"
+
+
+class VolumeCatcherImpl
+{
+};
+
+/////////////////////////////////////////////////////
+
+VolumeCatcher::VolumeCatcher()
+{
+	pimpl = NULL;
+}
+
+VolumeCatcher::~VolumeCatcher()
+{
+}
+
+void VolumeCatcher::setVolume(F32 volume)
+{
+}
+
+void VolumeCatcher::setPan(F32 pan)
+{
+}
+
+void VolumeCatcher::pump()
+{
+}
+