PARENTAL ADVISORY: explicit hack

This should allow volume control to (somewhat) work in LibVLC.
Unfortunately, it will still be buggy when there are multiple players.

This will probably never work for LibVLC.

This reverts commit cc4cabdf.

- searchLineEdit: proper clearing
- locationBar content will not affect searchLineEdit size

It closes the other part of #3161.

It partially closes #3161.

Add a third query with fuzzy search enabled for every word. (We could also add other searches with lower fuzzyness if the first try fails)

Try a second musicbrainz query if the first one failed. This allows for fuzzier matches (like not taking spaces into account in 1980 - 1990 for example) but still doesn't fix issues with minor spelling errors.

Attach the vout object to parent before spu creation so modules loaded by spu can use var inheritance.

(TODO: add one item per X RandR view port)

This simplifies callbacks a bit, and fixes a race condition.