Create 2013-10-17-xas-software

Create a _post for the Demeter package of software for XAS data analysis and processing, a project from a physicist at the United States' National Institute of Standards and Technology.
make .md extension on _post
trivial spelling correction
added some links to NIST
small edits
typo
update XAS Software post
Merge branch 'XAS_Software' of github.com:bruceravel/government.github.com into XAS_Software

Conflicts:
	_posts/2013-10-17-xas-software.md
more editing
typo
more chnages
more work
Update 2013-10-17-xas-software.md
Update 2013-10-17-xas-software.md
incorporate an excellent suggestion from @benbalter
remove links to all the synchrotrons

they don't really advance t he narrative
incorporate feedback from colleagues
added links to lists of synchrotrons
Update 2013-10-17-xas-software.md
Update 2013-10-17-xas-software.md