Update html5validator to 0.3.3

[php-coder]

See

• https://github.com/svenkreiss/html5validator/releases/tag/v0.3.2 (had a regression, see html5validator emits a lot of warnings after update #1156)
• https://github.com/svenkreiss/html5validator/releases/tag/v0.3.3

This also updates vnu.jar from 18.3.0 to 18.11.5

[php-coder]

We can also play with --also-check-css option.