/** \page sequences Sequences

\section bbExecute sequence



\arg The user calls bbtk::BlackBox::bbExecute on BlackBox B
\arg bbExecute calls bbtk::BlackBox::bbRecursiveExecute which is the main recursive execution method. It passes a NULL Connection to tell bbRecursiveExecute that the execution order did not come from an output connection.
\arg bbRecursiveExecute does:
     - returns if the box is already executing (cycle prevention) 
     - bbInitializeProcessing : initialize the box if not already done
     - Sets the box as executing: bbSetExecuting(true)
     - Stores the bool which tells if some other box is executing bbGlobalGetSomeBoxExecuting()
     - Sets the global flag which tells if some box is executing ( bbGlobalSetSomeBoxExecuting(true));



*/