standard 'py_compile.compile()' function.  Laundry list of features:
  - handles standard Distutils 'force', 'verbose', 'dry_run' flags
  - handles various levels of optimization: can compile directly in
    this interpreter process, or write a temporary script that is
    then executed by a new interpreter with the appropriate flags
  - can rewrite the source filename by stripping an optional prefix
    and preprending an optional base dir.