[Ifeffit] macports instructions

[Bruce Ravel]

Hi all,

In light of recent questions about the MacPorts package, I have updated 
the Mac installation instructions at the Demeter website.

This page:

 
http://bruceravel.github.io/demeter/documents/SinglePage/macinstallation.html

combines the basic instructions and includes a troubleshooting section 
that covers the "libcxx" issue.  The main Demeter web page now links to 
that page.

If some of you Mac users could give the new document a read and provide 
any suggestions for clarification or improvement, I would be grateful.

Cheers,
Bruce

-- 
  Bruce Ravel  ------------------------------------ bravel at bnl.gov

  National Institute of Standards and Technology
  Synchrotron Science Group at NSLS-II
  Building 743, Room 114
  Upton NY, 11973

  Homepage:    http://bruceravel.github.io/home/
  Software:    https://github.com/bruceravel
  Demeter:     http://bruceravel.github.io/demeter/