Merge pull request #234 from kaitlin/master

Sorting in API contracts endpoint
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fixed 'no matching contracts' indicator to not display when not needed
Fixes #196. Make NAICS short codes work with contracts loader
added 8a and hubzone tests, ignore python3 warnings
complete test backfill. closes #229
Merge pull request #235 from jroo/sb_notification

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made selenium tests headless
fixed conflicts
Merge pull request #237 from jroo/no_matching_contracts

Fixes for contract list bugs and test backfill
added link to vendor site
Merge pull request #239 from jroo/vendor_site

added link to vendor site
Merge branch 'master' of https://github.com/18F/mirage