Topology code for direct port calls with typed ports

[bocchino]

This PR adds code generation for direct calls with typed ports.

• Implement code generation
• Add unit tests

Code generation for serial ports is future work.

Further to #840.

[bocchino]

A couple of issues to fix, uncovered during integration:

• The generated code for ports uses #if FW_DIRECT_PORT_CALLS before it includes the config header. This works only if FW_DIRECT_PORT_CALLS is defined on the command line. We need to support setting it in the config header.
• The generated code for topologies uses #ifndef FW_DIRECT_PORT_CALLS instead of #if !FW_DIRECT_PORT_CALLS.

[bocchino]

Further issues uncovered during integration:

• The topology code gen is not generating the functions CComponentBase::p_isConnected and CComponentBase::p_out in the case that (1) component C has an output port p and (2) an instance of C is part of the topology and (3) there is no connection from c.p for any instance c of C. This causes a linker error. In this case we should generate code that returns false for p_isConnected and runs ASSERT(0) for p_out, since an unconnected port should not be invoked.
• The topology code gen does not correctly handle connections to the special input port cmd recv. The handlerBase calling protocol appears to be different than for general ports.