Treat empty comments as blank lines
Be more graceful if parsing fails
Add binary controls defaults page

Pablo has reformatted binary_controls.defaults to use the new
formatting.  This updates the website and associated machinery in order
to display this information.
Add temporary version of binary_controls.defaults

This commit adds the latest (non-release) version of
binary_controls.defaults.  This is confirmed to work with the website,
but needs to be updated to the latest version before release.
Merge branch 'maint'
Update 02-prereqs.markdown
Allow empty comments that have a space
Sync defaults files with MESA r7184
Announce release r7184
Update documention header
Merge branch 'maint'