Introduced WNumberDb, to display numeric volume and gain. Allow string substitution by %1 in WNumber.
added ratio2db() and db2ratio()
removed unused function
inherid WNumberDb from WNumber
Removed ConstFactor from WNumber. It was badly named, unused and undocumented.
We can acheve the same function by using Transform inside the connection.
Merge pull request #245 from daschuer/wnumberdb

WNumberDb a dB Display
DN-MC6000MK2: Initial revision
DN-MC6000MK2: Map some controls and the VU meter LEDs directly
DN-MC6000MK2: Looping

- Loops: Manual, beat and beatroll
- Censor: Use reverseroll instead of reverse
- Scratching: Don't modify keylock mode
DN-MC6000MK2: Track loading

- Solo cue mix when loading a track (can also triggered manually
  by pressing Shift + Cue Mix)
- Slip mode fixes (still does not always work as expected)
Fix compile errors in m4a decoder
DN-MC6000MK2: Samplers and various improvements

- 16 samplers (4 per deck)
- Hotcue fixes
- Sync mode switching improvements
- Use cue mix LEDs as track load indicator
- Delete obsolete filter controls
DN-MC6000MK2: Polishing

- Global shift state
- Slip mode fixes
- Looping improvements
- Cue button controls AutoDJ fade/skip
- Shift + play triggers stutter play
- Internal refactoring of hotcues
- Delete obsolete constants & triggers