Another round of effects bashing.

I've added some of the new plugin stuff to LV2, Nyquist, and
Vamp so that they play better in the new system.  They no
longer get bunched in with the Audacity effects when sorting
or grouping the menus.  They have not been fully converted
but they should be good for 2.1.0.

Nyquist plugins now include ";author" and ";copyright"
statements.

Added the 4 new Nyquist plugins to the Windows build.

Audiounits are still coming...had to push them to the back
burner to get this other stuff out of the way.

Scanning for new plugins has been improved so that newly
discovered ones will be shown to the user when Audacity starts.

Effects menu sorting has been fixed and improved.

Disabling effect types in Preferences works again and you
no longer have to restart Audacity for them the change to work.

Effect usage in chains works again.

Plugin registration dialog code simplified a bit.

Group names in the pluginregistry are now base64 encoded.  I
never really thought about it, but wxFileConfig group names
are case insensitive and since I was using the group name as
the plugin ID, I ran into a conflict on Linux where there
were two plugins with the same name, just different case.  (And
they were different plugins.)  Hoping all of this will change
when/if the config file gets converted to XML.  (wx3 if finally
including XML support)

A fair amount of cleanup of this new code has been done and
will continue as more stuff is converted.

include/audacity/ModuleInterface.h

@@ -74,7 +74,7 @@ public:
    virtual void Terminate() = 0;
 
    // Modules providing a single or static set of plugins may use
-   //  AutoRegisterPlugins() to register those plugins.
+   // AutoRegisterPlugins() to register those plugins.
    virtual bool AutoRegisterPlugins(PluginManagerInterface & pluginManager) = 0;
 
    // For modules providing an interface to other dynamically loaded plugins,
@@ -89,6 +89,10 @@ public:
    virtual bool RegisterPlugin(PluginManagerInterface & pluginManager,
                                const wxString & path) = 0;
 
+   // For modules providing an interface to other dynamically loaded plugins,
+   // the module returns true if the plugin is still valid, otherwise false.
+   virtual bool IsPluginValid(const PluginID & ID, const wxString & path) = 0;
+
    // When appropriate, CreateInstance() will be called to instantiate the plugin.
    virtual IdentInterface *CreateInstance(const PluginID & ID, const wxString & path) = 0;