add back TASK_LOST_WHILE_DOWN for compatibility

Fixes #256
should have no associated task state.
UI docs rewrite
Tiny aesthetic change
Added TL;DR
Remove $s for easier copy-pasting
Merge pull request #259 from HubSpot/improved-ui-docs

New SUI docs
use custom URL for node download
Remove $s and remove mention of building SUI
Merge pull request #260 from HubSpot/s3-nodejs

use custom URL for node download
Merge branch 'master' into hs_staging