Move flake8 checks to before_install
TEMP to fail flake8
Minor fixes

Re-organize jar, remove tabs
Minor fixes pointed out by @mtbc
flake8 cleanup of some test files
Minor typo fixes
Minor refactoring of BFPPB for testing

In order to be able to intercept (and block) certain
methods of BFPPB for concurrency testing methods have
been changed to `protected` and an `init()` method has
been introduced to allow a ctor with less logic.
Passing test with intermediate fix

The change (basically to not lock on read) makes
this test pass where before it was failing (when
`Thread.sleep()` was artificially introduced for
calls to releaseLock.

It's unknown if this will be sufficiently safe
going forward.
merge develop -D org -I include -E exclude: PR 1385 (Update the OMERO VirtualBox image)
merge develop -D org -I include -E exclude: PR 1712 (Create release source artifact containing all submodules)
merge develop -D org -I include -E exclude: PR 1733 (Preventing system users being removed from system groups)
merge develop -D org -I include -E exclude: PR 1753 (Edit user)
merge develop -D org -I include -E exclude: PR 1756 (Exclude the import log from the list of files.)
merge develop -D org -I include -E exclude: PR 1779 (Copy rendering 11552)
merge develop -D org -I include -E exclude: PR 1800 (Simple salting of MD5 passwords (See #1387))
merge develop -D org -I include -E exclude: PR 1811 (11607 scripts)
merge develop -D org -I include -E exclude: PR 1818 (Error handling of tile image loading in PanoJS See #11709)
merge develop -D org -I include -E exclude: PR 1820 (Worked around method_decorator problem with custom getattr)
merge develop -D org -I include -E exclude: PR 1822 (Script parameter)
merge develop -D org -I include -E exclude: PR 1824 (Initialize table before file chooser.)