Changes:
* Terminate all namespaces with the correct closing comment.
* Make sure argument names in comments match the corresponding parameter name.
* Remove redundant get() calls on smart pointers.
* Prefer using "override" or "final" instead of "virtual". Remove "virtual" where appropriate.
This enables one to dump the various passpipelines in a yaml format. Other
pretty print formats can be added in the future as well if desired. Its intended
usage is to provide a source of pass pipeline information for external python
bug-reducing tools. By integrating this as a compiler-tool, we are guaranteed to
never have to update any of these tools in the face of passpipeline changes.
