Backport HTMLX Settings

[SLaks]

VS2013 introduced the new HTMLX editor, which replaces the old HTML editor for everything except ASPX.

The properties for the old HTML editor are not saved by default, since they throw exceptions that slow things down unacceptably. (see https://gist.github.com/SLaks/7999962)

Ideally, we should apply HTMLX-Specific properties to HTML Specific as well, and detect changes to either set of properties when saving changes (which may be tricky).
This will require a mapping of new property names to old ones.

Until this is implemented, HTML settings will only be applied to VS2013+.