Extracted common code out to SS_HTMLValue and made abstract, then
put HTML 4 specific code in SS_HTML4Value. Its now possible to
replace HTMLValue with one designed for HTML 5 or XHTML
Requires a code change from new SS_HTMLValue to
Injector::inst()->create(HTMLValue)
API Added Convert::nl2os function to normalise end of line characters across systems with tests
BUG Fixed i18n unit tests in non-unix systems constantly failing
BUG Fixed problems with HTMLCleaner tests failing in non-unix systems