Javadoc cleanup for the new public clustering API
[WFLY-2895] Fix NPE if async method with void return type is invoked remotely
[WFLY-2896] Fix possible NPE in link lookup
Merge pull request #5897 from dmlloyd/wfly-2895-async-npe

[WFLY-2895] Fix NPE if async method with void return type is invoked remotely
Merge pull request #5898 from dmlloyd/wfly-2896-link-npe

[WFLY-2896] Fix possible NPE in link lookup
Merge pull request #5896 from ctomc/undertow

Don't use persistent sessions by default
Fix WFLY-2901.
Merge pull request #5893 from rhusar/javadoc_clustering_api

Javadoc cleanup for the new public clustering API
Merge pull request #5900 from jfclere/master

Fix WFLY-2901.
Fix quickstart link
Release 8.0.0.Final
Next is 8.0.1.Final
Change IO defaults