Resolve "New data structure for storing stateblocks"

Closes #256 (closed)

include/core/capture/capture_base.h

@@ -81,7 +81,7 @@ class CaptureBase : public NodeBase, public HasStateBlocks, public std::enable_s
         const FactorBasePtrList& getConstrainedByList() const;
 
         // State blocks
-        std::string getStructure() const;
+        const std::string& getStructure() const;
         StateBlockPtr getStateBlock(const std::string& _key) const;
         StateBlockPtr getStateBlock(const char _key) const { return getStateBlock(std::string(1, _key)); }
         StateBlockPtr getSensorP() const;