target-test-runner: exclude package and log4j jars

Fixes #12114.
MRC: fix handling of mode 16 data

Mode 16 denotes 8-bit RGB data, not 16-bit data.  See
https://trello.com/c/guQdSW8V/235-follow-ups-with-joaquin
Remove JENKINS_JOB variable and point at the release components
Add extlink for source directories and fix links across doc
Miscellaneous redirects
Redirect svn.openmicroscopy.org.uk links
Redirect http://loci.wisc.edu/software links
Merge pull request #1091 from melissalinkert/mrc-pixel-type

MRC: fix handling of mode 16 data
Deprecate download_components in favor of downloads extlink
Point at other artifacts  directly using the downloads extlink
Merge pull request #1080 from melissalinkert/test-runner-classpath

Exclude log4j and packages from target-test-runner
Merge pull request #1093 from sbesson/jenkins_docs_cleanup

BF docs: Jenkins cleanup