Fix errors and warnings.

[mounirlamouri]

This is fixing the following:

• missing references;
• normative references on non-normative sections;
• update HTML51 to HTML;
• add mandatory [Exposed=Window] tagging;
• update constructor syntax.

[mounirlamouri]

@wolenetz PTAL. Note that it's including my other PR so I will have to rebase after you merge.

[mounirlamouri]

PTAL