Add apostrophe

Is this really that important? Must ask my therapist...
Merge pull request #43 from alphagov/add-search

Add search
Tidy measurement URLs
Update measurement URLs
Remove duplicate
Clean Research URLs
Tidy URLs
Fix bad phase name in link
Include contributions from Josh and Brad
Remove full stops from eg

Style guide FTW.
Updated text with agreed doc
Added assisted digital line
Create page
Rename spending-controls to spending-controls.md
Remove caveat notice
Fixed bullets
added video link
Add disclaimer to footer
Added link, minor tweaks
Tweaked text,deleted unnecessary line