[pymtl/tools/integration] Add a method of compiling a single cc file
[pymtl/tools/integration] Add a method of compiling a single cc file

The compile_object method is used to compile, e.g., a.cc, into a.o.

The method is called by caching resolver which only recompiles
uncached modules to save time.

cornell-brg/pymtl,cornell-brg/pymtl,cornell-brg/pymtl