update Changelog from upstream
actually there is no need for c-auto.h
add mom example

verbatim copy of mom-2.0-a_1/examples/mom-pdf.mom
add refer example usage, mostly taken out of moms online documentation
initial import of http://lists.gnu.org/archive/html/groff/2012-09/msg00070.html

Striped index makros of markus macro package http://www.oxytropis.plus.com/groff/
Add a minimal yet working indexing example for MOM

Excute it with
  pdfmom -U -R -mindex mom-pdf.mom > mom-pdf.mom.pdf

(-U implies -M.; otherwise the style file will be loaded from the TMAC directory or `TMAC_directory/INS`
Add a PDF example

No good git habit but easy to demonstrate