Changed: less redundancy in DoCommonSy().
Changed: Symb separated into TElemSymb and TAttrSymb.
Removed: Special handling of HeadingSy. Replaced with symbols H1Sy..H6Sy resp. H1EndSy..H6EndSy.
Merge branch 'HtmlViewer11' of git://github.com/BerndGabriel/HtmlViewer

Conflicts:
	source/HTMLUn2.pas
	source/ReadHTML.pas