some strategic documentation

Prevent class descriptions inheriting the doc from PBD:Stateful by
adding some specific doc.

libs/ardour/ardour/location.h

@@ -164,6 +164,7 @@ class LIBARDOUR_API Location : public SessionHandleRef, public PBD::StatefulDest
 	void recompute_bbt_from_frames ();
 };
 
+/** A collection of session locations including unique dedicated locations (loop, punch, etc) */
 class LIBARDOUR_API Locations : public SessionHandleRef, public PBD::StatefulDestructible
 {
   public:

libs/ardour/ardour/plugin.h

@@ -55,6 +55,14 @@ typedef boost::shared_ptr<Plugin> PluginPtr;
 typedef boost::shared_ptr<PluginInfo> PluginInfoPtr;
 typedef std::list<PluginInfoPtr> PluginInfoList;
 
+/** A plugin is an external module (usually 3rd party provided) loaded into Ardour
+ * for the purpose of digital signal processing.
+ *
+ * This class provides an abstraction for methords provided by
+ * all supported plugin standards such as presets, name, parameters etc.
+ *
+ * Plugins are not used directly in Ardour but always wrapped by a PluginInsert.
+ */
 class LIBARDOUR_API Plugin : public PBD::StatefulDestructible, public Latent
 {
   public:

libs/ardour/ardour/track.h

@@ -35,6 +35,11 @@ class Region;
 class Diskstream;
 class IO;
 
+/** A track is an route (bus) with a recordable diskstream and
+ * related objects relevant to tracking, playback and editing.
+ *
+ * Specifically a track has regions and playlist objects.
+ */
 class LIBARDOUR_API Track : public Route, public PublicDiskstream
 {
   public:

libs/ardour/route.cc

@@ -79,6 +79,7 @@ using namespace PBD;
 PBD::Signal0<void> Route::SyncOrderKeys;
 PBD::Signal0<void> Route::RemoteControlIDChange;
 
+/** Base class for all routable/mixable objects (tracks and busses) */
 Route::Route (Session& sess, string name, Flag flg, DataType default_type)
 	: SessionObject (sess, name)
 	, Automatable (sess)

libs/pbd/pbd/command.h

@@ -28,6 +28,7 @@
 #include "pbd/signals.h"
 #include "pbd/statefuldestructible.h"
 
+/** Base class for Undo/Redo commands and changesets */
 class LIBPBD_API Command : public PBD::StatefulDestructible, public PBD::ScopedConnectionList
 {
 public:

libs/pbd/pbd/controllable.h

@@ -37,7 +37,7 @@ class XMLNode;
 
 namespace PBD {
 
-/* This is a pure virtual class to represent a scalar control.
+/** This is a pure virtual class to represent a scalar control.
  *
  * Note that it contains no storage/state for the controllable thing that it
  * represents. Derived classes must provide set_value()/get_value() methods,
@@ -49,7 +49,6 @@ namespace PBD {
  * as a control whose value can range between 0 and 1.0.
  *
  */
-
 class LIBPBD_API Controllable : public PBD::StatefulDestructible {
   public:
 	enum Flag {

libs/pbd/pbd/id.h

@@ -29,6 +29,7 @@
 
 namespace PBD {
 
+/** a unique ID to identify objects numerically */
 class LIBPBD_API ID {
   public:
 	ID ();