Generalise progress tracking to allow multiple progress updates

* We track the progress through making a capture as well as the progress
  we already tracked loading a capture.
* Also incidentally fix a copy-paste bug that was calculating the wrong
  progress for loading captures by applying FileInitialRead instead of
  FrameEventsRead for the frame replay.

renderdoc/core/remote_server.cpp

@@ -406,7 +406,7 @@ static void ActiveRemoteClientThread(ClientThread *threadData)
           bool kill = false;
           float progress = 0.0f;
 
-          RenderDoc::Inst().SetProgressPtr(&progress);
+          RenderDoc::Inst().SetProgressPointer<LoadProgress>(&progress);
 
           Threading::ThreadHandle ticker = Threading::CreateThread([&writer, &kill, &progress]() {
             while(!kill)
@@ -439,7 +439,7 @@ static void ActiveRemoteClientThread(ClientThread *threadData)
             }
             else
             {
-              RenderDoc::Inst().SetProgressPtr(NULL);
+              RenderDoc::Inst().SetProgressPointer<LoadProgress>(NULL);
 
               kill = true;
               Threading::JoinThread(ticker);