Implementation of AutoStile.

This class can be used to make the execution of a sibling (slave) context dependent on the exaction of the (master) context enclosing AutoStile.
AutoStile injects data from the master context and extracts data from the slave context, according to its template arguments.
Unit test demonstrating use of AutoStile.
Removing assumption of context from AutoPacketFactory pipe & broadcast declarations.
Adding comments to AutoCheckout explaining avoidance of std::shared_ptr<AutoPacket>.
Adding AutoMergeStile to facilitate extraction of data gathered by AutoMerge. Also added helper PipeToMerge method.
Adding unit test demonstrating use of AutoMergeStile.