Merge branch 'master' into bugfix/UIMA-6275-InitializableFactory-is-not-smart-enough-to-find-a-suitable-classloader

* master: (130 commits)
  [UIMA-6263] CAS validation support
  [UIMA-6264] Switch from DocBook to Asciidoc
  [UIMA-6257] Jenkinsfile for uimaFIT
  [UIMA-6257] Jenkinsfile for uimaFIT
  [UIMA-6257] Jenkinsfile for uimaFIT
  [UIMA-6257] Jenkinsfile for uimaFIT
  [maven-release-plugin] prepare for next development iteration
  [maven-release-plugin] prepare release uimafit-3.1.0
  [maven-release-plugin] prepare for next development iteration
  [maven-release-plugin] prepare release uimafit-3.1.0
  [NO JIRA] Adjust UIMA version in the NOTICE file of the binary distribution
  [maven-release-plugin] prepare for next development iteration
  [maven-release-plugin] prepare release uimafit-3.1.0
  [NO JIRA] Update documentation to changed API in ExternalResourceFactory and removed a spurious character
  [NO JIRA] Adjusted comparison version for API change report
  [NO JIRA] Updated README file for release.
  [NO JIRA] Updated README file for release.
  [UIMA-6214] Method signature class in ExternalResourceFactory
  Update an Eclipse metadata file.
  [UIMA-5847] Remove UV3 bug workarounds in FSCollectionFactory
  ...

# Conflicts:
#	uimafit-core/src/main/java/org/apache/uima/fit/factory/FsIndexFactory.java
#	uimafit-core/src/main/java/org/apache/uima/fit/factory/TypePrioritiesFactory.java
#	uimafit-core/src/main/java/org/apache/uima/fit/factory/TypeSystemDescriptionFactory.java
#	uimafit-core/src/main/java/org/apache/uima/fit/internal/ResourceManagerFactory.java