youtube-dl: revert Python 2.x and 3.x support

This makes youtube-dl harder to use as just a script, and people who
need it to call it from python can just install via pip.

This reverts commit e83a9bec485e218dd449df93c5564c834fde1a2a.
riemann 0.2.2

Closes #20353.

Signed-off-by: Jack Nagel <jacknagel@gmail.com>
FormulaInstaller: factor out readline workaround
vera++ 1.2.1

Closes #20356.

Signed-off-by: Adam Vandenberg <flangy@gmail.com>
git: add note about 1.8.3 being broken
Sniff for non-tarred gzips

Don't try to untar non-tarred gzips.
tesseract: use normal download strategy
graphviz: update --devel version
Ghostscript: add DjVU support

Closes #16830.

Signed-off-by: Adam Vandenberg <flangy@gmail.com>
cmake: simplify test slightly
Implement resources
Use resources
wip
wip
wip
wip
wip
wip tesseract
wip