remove compat: `password` property in `html:TextInput`

This removes the `password` config property of `html:TextInput`.
Use `attribute.type = password` instead.

(deprecated in 1.4.6 via GH-551)
remove compat: non-standard dataset keys in utils.Html

This removes backward compat when the user was using non-standard
dataset keys in `aria.utils.Html` methods.

(deprecated in 1.4.7 via GH-499)
remove compat: `cssClass` in sections and repeaters

This removes backward compat for cssClass property in sections
and repeaters. Please use `attributes.classList` instead.

(deprecated in 1.5.2 via GH-1086)
remove compat: `escape` modifier

This removes the `escape` modifier available in the templates.
Please use `escapeforhtml` modifier instead.

(deprecated in 1.5.3 via GH-1099)
remove compat: unused jsunit classes

This removes some `aria.jsunit.*` classes that are no longer supported.

(deprecated in 1.5.3 via GH-1104)
remove compat: `onpopstate` event from utils.History

This removes compat for `onpopstate` event raised by aria.utils.History.
Use `popstate` event instead.

(deprecated in 1.6.3 via GH-1124)