Refactor public interface to be less strict C and more python friendly

* Generally this means removing ref out parameters and instead returning
  values. In a couple of cases we will want to avoid copies in future
  either by returning const references (e.g. to the pipeline state which
  is immutable).
* At the same time, some pointless bool return values that were always
  true and didn't indicate errors have been removed. They can be added
  again if an error condition comes back.
* Some free functions still have out parameters as C linkage doesn't
  allow returning user types by value.
* The C# UI still invokes into C wrappers for all the C++ classes, which
  handle taking the return value and doing a copy into an out parameter
  still for compatibility.

qrenderdoc/Windows/MainWindow.cpp

@@ -381,7 +381,7 @@ void MainWindow::OnInjectTrigger(uint32_t PID, const QList<EnvironmentModificati
                                            env[i].value.toUtf8().data(), env[i].type,
                                            env[i].separator);
 
-    uint32_t ret = RENDERDOC_InjectIntoProcess(PID, envList, logfile.toUtf8().data(), &opts, false);
+    uint32_t ret = RENDERDOC_InjectIntoProcess(PID, envList, logfile.toUtf8().data(), opts, false);
 
     RENDERDOC_FreeEnvironmentModificationList(envList);
 
@@ -959,8 +959,7 @@ void MainWindow::messageCheck()
   if(m_Ctx.LogLoaded())
   {
     m_Ctx.Renderer().AsyncInvoke([this](IReplayRenderer *r) {
-      rdctype::array<DebugMessage> msgs;
-      r->GetDebugMessages(&msgs);
+      rdctype::array<DebugMessage> msgs = r->GetDebugMessages();
 
       bool disconnected = false;