code: use config macro

Macro is much easier to use and more readable

app/render/diskmanager.cpp

@@ -196,7 +196,7 @@ DiskCacheFolder::DiskCacheFolder(const QString &path, QObject *parent) :
 {
   SetPath(path);
 
-  save_timer_.setInterval(Config::Current()[QStringLiteral("DiskCacheSaveInterval")].toInt());
+  save_timer_.setInterval(OLIVE_CONFIG("DiskCacheSaveInterval").toInt());
   connect(&save_timer_, &QTimer::timeout, this, &DiskCacheFolder::SaveDiskCacheIndex);
   save_timer_.start();
 }

app/render/previewautocacher.cpp

@@ -48,7 +48,7 @@ PreviewAutoCacher::PreviewAutoCacher() :
   SetPlayhead(0);
 
   // Wait a certain amount of time before requeuing when we receive an invalidate signal
-  delayed_requeue_timer_.setInterval(Config::Current()[QStringLiteral("AutoCacheDelay")].toInt());
+  delayed_requeue_timer_.setInterval(OLIVE_CONFIG("AutoCacheDelay").toInt());
   delayed_requeue_timer_.setSingleShot(true);
   connect(&delayed_requeue_timer_, &QTimer::timeout, this, &PreviewAutoCacher::RequeueFrames);
 
@@ -502,8 +502,8 @@ void PreviewAutoCacher::StartCachingAudioRange(const TimeRange &range)
 
 void PreviewAutoCacher::SetPlayhead(const rational &playhead)
 {
-  cache_range_ = TimeRange(playhead - Config::Current()[QStringLiteral("DiskCacheBehind")].value<rational>(),
-      playhead + Config::Current()[QStringLiteral("DiskCacheAhead")].value<rational>());
+  cache_range_ = TimeRange(playhead - OLIVE_CONFIG("DiskCacheBehind").value<rational>(),
+      playhead + OLIVE_CONFIG("DiskCacheAhead").value<rational>());
 
   RequeueFrames();
 }

app/render/renderprocessor.cpp

@@ -106,7 +106,7 @@ FramePtr RenderProcessor::GenerateFrame(TexturePtr texture, const rational& time
       if (output_color_transform) {
         // Yes color transform, blit color managed
         render_ctx_->BlitColorManaged(output_color_transform, texture,
-                                      Config::Current()[QStringLiteral("ReassocLinToNonLin")].toBool() ? Renderer::kAlphaAssociated : Renderer::kAlphaNone,
+                                      OLIVE_CONFIG("ReassocLinToNonLin").toBool() ? Renderer::kAlphaAssociated : Renderer::kAlphaNone,
                                       blit_tex.get(), true, matrix);
       } else {
         // No color transform, just blit