* Do not call bootstrap.py because it downloads waf-1.8.12 in BUILD!
Instead, add a SOURCE_URI_2 for waf-1.8.12 and mimic bootstrap.py.
* Use tar.gz (instead of zip) in SOURCE_URI. (identical contents)
* Add SOURCE_FILENAME. (v0.23.0.tar.gz -> mpv-0.23.0.tar.gz)
* Drop unneeded SOURCE_DIR.
* Switch HOMEPAGE to https.
* Clipdinger needs a new revision for a recompile to fix the splitview
drawing issue caused by some changes a while ago.
* MPV needed a "keep-old" for the global writable files to fix a policy
issue.