add error message to form helpers
remove skrollr, use flexbox to vertically align video
Merge branch 'master' of github.com:optimizely/marketing-website into dfoxpowell/optimizely-org-page
Merge pull request #543 from optimizely/dfoxpowell/optimizely-org-page

add error message to form helpers
Encode try it out URLs.
Merge pull request #544 from optimizely/krush/url

Encode try it out URLs.
Update tracking and fix webinar email bug.
Merge pull request #548 from optimizely/krush/form-submission

Update tracking and fix webinar email bug.
Fix experiment nav results bug.
Merge pull request #549 from optimizely/krush/results

Fix experiment nav results bug.
Merge branch 'master' into ssmith/form-error-removal