take article title from metadata, not filename
manual ordering of sidebar sections close #54

only problem: now the sort order is part of the article filename and
therefore the URL as well. had to manually change all links. if we
change the order of an article or section, anything that links to that
article or section will have to be changed too. the search index will
also have to update to reflect the new file paths.

`grunt link-checker` (nice to have this now) was all clear, so we
should be good to go.
new implementation of manual ordering

article order is defined by the metadata ‘order: x’ where x is an
integer that designates the article’s order in that section.

section order is defined in the `config.json` file, under
locals->section_sort_order.

this avoids having any messy numbers in the file or folder names.

ran `grunt link-checker` to make sure no links are bad from the
transition.
Merge pull request #57 from dobtco/master

Deploy to production