The new_importers code now works better, and passes more stringent unit tests, than the old.
In particular, unit tests for rST code now actually exercise the rST importer code.
To make this work, the comparison code for rST files replaces all under/overline line with a "standard" line.   Not perfect, but it's important not to be too picky when doing the perfect import check.  Hehe.