ant: Add ant build logic for sphinx documentation
travis: Use ant to build documentation
travis: Install ant-contrib
travis: Install ant-optional
ant: Move taskdef to rules.xml
travis: Explicitly set CLASSPATH
ant: Add linkcheck targets
README: Document ant usage
Remove formats & contributing from build.xml

These document sets don't exist on this branch, they are only maintained on develop
Delete contributing/build.xml
Delete formats/build.xml
merge dev_5_0 -D org: PR 746 (Use ant to build sphinx docs (rebased onto dev_5_0))
merge dev_5_0 -D org

Repository: openmicroscopy/ome-documentation
Already up-to-date.

Merged PRs:
  # PR 746 hflynn 'Use ant to build sphinx docs (rebased onto dev_5_0)'

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