Support variation of HTML5 signature:

<!DOCTYPE html SYSTEM "about:legacy-compat">

This is an alternative for HTML generators that don't support DOCTYPE html.  XSLT is an example of such a generator.
Merge branch 'HtmlViewer-11.4-to-11.5' of https://github.com/BerndGabriel/HtmlViewer into HtmlViewer-11.4-to-11.5
Issue 319: Viewer.CopyToClipboard error
Changed: still not supporting display:inline
- Excluded incomplete code
Fixed: compiler version table
Merge branch 'HtmlViewer-11.4-to-11.5' of https://github.com/BerndGabriel/HtmlViewer into HtmlViewer-11.4-to-11.5
Issue 339: Viewer.CopyToClipboard error
Merge branch 'HtmlViewer-11.4-to-11.5' of https://github.com/BerndGabriel/HtmlViewer into HtmlViewer-11.4-to-11.5
Issue 339: Viewer.CopyToClipboard error
Merge branch 'HtmlViewer-11.4-to-11.5' of https://github.com/BerndGabriel/HtmlViewer into HtmlViewer-11.4-to-11.5
Added: THtmlViewer publishes gesture properties
Added: Lazarus can print now.
Added: class_hierarchy.htm
Updated: type_tincludetype.htm
Merge branch 'HtmlViewer-11.4-to-11.5' of https://github.com/BerndGabriel/HtmlViewer into HtmlViewer-11.4-to-11.5
Added: Delphi XE6 package files
Fixed: access violation drawing cell background
Lazarus loads non ANSI files.
Merge branch 'HtmlViewer-11.4-to-11.5' of https://github.com/BerndGabriel/HtmlViewer into HtmlViewer-11.4-to-11.5
Fixed XE6 MainDemo compile

About box did not have XE6 reference
Merge pull request #68 from MartinSedgewick/HtmlViewer-11.4-to-11.5

Fixed XE6 MainDemo compile