Mixxx 2.4.1

What's new in this version:

Controller Mappings:
- Behringer DDM4000 & BCR2000: Fix exception in JS code
- Denon DJ MC6000MK2: Fix mapping of filter knob/button
- Denon DJ MC7000: Fix redundant argument and migrate to hotcue_x_status
- Hercules Inpulse 200: Configure shift-browser knob to scroll the library (quick)
- Pioneer DDJ-FLX4: Add waveform zoom and other mapping improvements
- Traktor Kontrol F1: Fixes for hid-parser and related script
- Traktor S2 Mk1: fix warnings
- Traktor S3: Fix mapping crash on macOS
- Controller I/O table: sort action column by display string

Target Support:
- Fix various minor build issues
- CMakeLists: Always prefer OpenGL framework on macOS

Skins:
- Deere: make sampler rows persist
- Tango: Remove unneeded waveform Singleton
- Prevent possible crash in customs skins using parallel waveforms
- Slider tooltip: consider orientation for up/down shortcut tooltips + add support for WKnobComposed
- Tooltips: update 'hotcue' with saved loop features
- Animate long press latching of sync button
- Polish fx chain controls

Library:
- Sidebar: show track count and duration of History playlists
- Computer feature: update removable devices on Linux
- Playlists: Prevent removing tracks from locked playlists
- History feature: Fix removing deleted tracks after export
- BPM display uses decimal separator of selected locale
- Fix relink directory when migrate between Linux/macOS and Windows
- Allow adding new directories while watched directories are missing
- Require a minimum movement before initiating the drag&drop of tracks
- iTunes/Serato/Traktor/Rhythmbox: Print error if library file could not be opened
- Playlists: improve table update after deleting (purging) track files
- Fix Color column width issue
- Tracks: select track row when clicking the preview button (only when starting preview)
- Library track menu: show Hide action also in Playlist & Crates

Miscellaneous:
- Remove unnecessary unpolish operation of the style, before polish the new style
- Developer Tools: Initially sort controls by group name, ascending
- Waveforms: Fix scratching crossing loop boundaries
- Prohibit un-replace when deck is playing
- Track Properties dialog: Prevent wiping metadata when applying twice quickly
- AutoDJ: Fix button state after error message about playing deck 3/4
- Tagfetcher: Cache fetched covers
- Avoid beats iterator being one off and DEBUG_ASSERT in Beats::iteratorFrom
- Show hint if resource path in CMakeCache.txt does not exist
- Always calculate the auto value for colorful console output.
- Fix FLAC recording on macOS and Windows