Merge pull request #69 from mathjax/v4-update

V4 update

Merge pull request #49 from mathjax/update_demos

Update demos

Fix toArray() calls

Update puppeteer package.json

Merge branch '3.1.3-update'

Update *-page to not include styles if no math is found (speech version)

Update *-page to not include styles if no math is found (speech version)

Update *-page to not include styles if no math is found (speech version)

Update version to 3.0.5

Add release number shield to README