use hardcoded namespace

The macro defined namespaces confused the hell out of lupdate and more or less broke translations permanently. Looks like the only way we can do it is to have a hardcoded namespace, which goes against my instinct, but honestly how likely is it that we'll change the namespace anyway (I guess forks might want to do it, but that's their problem ;) )

app/render/playbackcache.cpp

@@ -27,7 +27,7 @@
 #include "project/project.h"
 #include "render/diskmanager.h"
 
-OLIVE_NAMESPACE_ENTER
+namespace olive {
 
 void PlaybackCache::Invalidate(const TimeRange &r)
 {
@@ -195,4 +195,4 @@ QString PlaybackCache::GetCacheDirectory() const
   }
 }
 
-OLIVE_NAMESPACE_EXIT
+}