various: encapsulate all code in the olive namespace to avoid name collisions

Large-scale code cleanup. Also adds a license to the top of all files that were
missing it.

app/node/output.h

@@ -24,6 +24,8 @@
 #include "common/timerange.h"
 #include "param.h"
 
+OLIVE_NAMESPACE_ENTER
+
 /**
  * @brief A node parameter designed to serve data to the input of another node
  */
@@ -50,4 +52,6 @@ private:
 
 };
 
+OLIVE_NAMESPACE_EXIT
+
 #endif // NODEOUTPUT_H