code: @Override
      public boolean matches(Source src) {
          String name = src.getOrigin().getName().toLowerCase();
          if (FilenameUtils.isExtension(name, new String[]{"markdown", "md"})) {
              return true;
          }
          if ("post".equals(src.getMeta().get("layout")) && FilenameUtils.isExtension(name, "txt")) {
              return true;
          }
          return false;
      }
docs: /* (non-Javadoc)
  @see org.opoo.press.Converter#matches(org.opoo.press.Source)