Lib control & navigation optimizations -combined-

[ronso0]

I merged #2597 #2598 #2599 #2628 #2632 for personal use, and I can as well share it here.
Facilitates building, in case someone likes to test those with a controllers.
(not for code review!)

With controller you can test

Library navigation
Navigation with [Library],controls should feel exactly like with arrow & Tab keys on a keyboard.
[Library],MoveFocus... should always move the focus like tab key does.
No more getting stuck at the searchbox' Clear button, no more tabbing through AutoDJ button row etc.

If any non-library widget has focus (Beatsize spinbox or effect selector), issueing a scroll command [Library],Move... or [Library],Scroll... should always re-focus the tracks table (or library feature root view).
Check: when scrolling in any feature's track table with these controls, there should not pop up any additional "Tab key" events in the log stream.

[Playlist],SelectPlaylist and [Playlist],SelectTrackKnob should work as before.

Clear search from controller
Enter a search term, focus tracks table or anything else, then use Tab or [Library],MoveFocus... to focus the Clear button. Use [Library],GoToItem to clear the searchbox.

[JosepMaJAZ]

Ok, I tried this with the Mixtrack platinum mapping.

• "tab" ( shift + browse push ) works as expected going from library to side, as well as opening crates, libraries, computer and history. it does not open autodj or tracks but probably this is unrelated.

• Filtering and browsing sets the focus back to library, so nice to easily navigate.

• When filtered, tab goes to filter clear button which helps clearing the filter when pushing the browse knob.

• Doesn't "tab" to strange places.

• Strange places don't get focus ( can change effects, click the deck options, change skin settings...

But remains one small glitch that is unusual: Application needs focus, else navigation does not work. Mappings that use the older controls are not affected.
It is a consequence of using the "focus". Still, it should be possible to know which control was focused before.

[ronso0]

Thank you for testing!

it does not open autodj or tracks but probably this is unrelated.

I didn't touch that. I noticed this as well, but I assume it's by design to not enter those features because a) you can't do anything there (AutoDJ crates) or b it's unlikely that someone wants to go to Hidden or Missing via controller during a performance; wanting to jump from Tracks item to Tracks table i smuch more likely.

But remains one small glitch that is unusual: Application needs focus, else navigation does not work. Mappings that use the older controls are not affected.

I'll have look.
The point is, the lib navigation is mostly key presses, and those need an active window to be sent to. I'm not sure how we can enforce this once Mixxx was opened.
Btw, trying to get rid of those emulated keypresses is on my ToDo, but it's bit more complex..