Docs: Config docs + INI parser integration fixes

*  Reimplemented ConfigIniParser as a tuple,
   fix handling of many corner-cases with ini-parsing.
*  Reimplement NoOverwriteDict class as named tuple
   with several properties for commonly accessed items.
*  Moved generic translater methods back onto DocBase
   for use across all subclasses.
*  Added a doctree -> text method
*  Removed unnecessary RSTDoc subclass because...
*  Changed default render (conv) method on SubtestDoc
   to raw (i.e. rst) output, now other formats are optional.
*  Included & Adapted Sphinx's rst -> text writer
   for documentation module use.  Added textwriter module.
*  Added a text-summary render (conv) method to SubtestDoc
   relying on textwriter module/class for rendering.
*  Updated Makefile and Unittests

Signed-off-by: Chris Evich <cevich@redhat.com>