Merge branch 'master' into develop
Fix topichead with chunk and copy-to #1529
Fix merging ID bug with duplicate topics dita-ot/dita-ot#1528
Merge pull request #1530 from jelovirt/feature/duplicate_topic_merge

Fix merging ID bug with duplicate topics dita-ot/dita-ot#1528
Clean quick start guide map

Use copy-to to make installing-full-easy.dita unique in user documentation.
New website transtype #1533
Use class value instead of QName #1535
Fix transtype XPath guard in conref stylesheet
Fix and simplify title whitespace normalization #1537
Fix absolute PDF image reference #1538
Add documentation website specific DITA map
Update release notes for 1.8.1
Merge branch 'hotfix/1.8.1' into develop
Merge branch 'develop' into v2/develop