Add all the boilerplate for the Vst3PluginBridge

And now that I also have an idea of what the communication model will
look like, this can server as a base for instantiating plugins.

src/common/communication/vst3.h

@@ -29,6 +29,9 @@
  * sockets, and the call to `connect()` will then accept any incoming
  * connections.
  *
+ * TODO: I have no idea what the best approach here is yet, so this is very much
+ *       subject to change
+ *
  * @tparam Thread The thread implementation to use. On the Linux side this
  *   should be `std::jthread` and on the Wine side this should be `Win32Thread`.
  */
@@ -62,4 +65,10 @@ class Vst3Sockets : public Sockets {
         // Manually close all sockets so we break out of any blocking operations
         // that may still be active
     }
+
+    // TODO: I still don't know if recursive callbacks are a thing in VST3. If
+    //       not, then we should probably have two `AdHocSocketHandler`s per
+    //       plugin instance (one for each direction, as with `dispatcher()` and
+    //       `audioMaster()` in VST2). Using fewer probably also works, but we
+    //       wouldn't want to have to spawn new sockets during audio processing.
 };

src/common/logging/vst2.h

@@ -32,6 +32,9 @@
  */
 std::optional<std::string> opcode_to_string(bool is_dispatch, int opcode);
 
+/**
+ * Provides VST2 specific logging functionality for debugging plugins.
+ */
 class Vst2Logger : public Logger {
    public:
     // The following functions are for logging specific events, they are only

src/common/logging/vst3.h

@@ -0,0 +1,27 @@
+// yabridge: a Wine VST bridge
+// Copyright (C) 2020  Robbert van der Helm
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+#pragma once
+
+#include "common.h"
+
+/**
+ * Provides VST3-specific logging functionality for debugging plugins.
+ */
+class Vst3Logger : public Logger {
+   public:
+    // TODO: Logging interface for VST3 plugins
+};