Vestax VCI-300: Jog control improvements

2013-05-30:
- Ignore jog wheel movements unless the jog wheel surface is touched.
  Exception from this rule: Nudging when playing in scratch mode is
  still possible without touching the sensor plate!
- Different jog sensitivity parameters for cueing and nudging (tempo)
- Increased jog sensitivity for both cueing and nudging

See also:
http://www.mixxx.org/forums/viewtopic.php?f=7&t=4021&start=20#p18581
Vestax VCI-300: Borrow some ideas from Serato DJ

2013-10-05:
- Pitch Bend (Pitch Shift)
- Pitch Adjust (Shift + Pitch Shift)
- Stutter Play (Shift + Play)
Vestax VCI-300: Bugfix for broken backspin

2013-10-05:
- Fix broken backspin (regression introduced with version 2013-05-30)
Vestax VCI-300: Fix stutter play

2013-10-05.1:
- Fix behavior of stutter play using the latest position
  where playing started. The previous implementation was
  completely different from that found in Serato DJ.
- Some minor changes to reflect the values that would
  need to be reset on track load. Unfortunately there's
  no appropriate callback in Mixx to invoke this function.
Vestax VCI-300: Full-featured stutter play implementation

2013-10-06:
- Stutter play now takes the cue point and also triggering
  of hotcues into account.
- Update documentation
- Internal refactoring and minor fixes
Vestax VCI-300: Improve stutter play implementation

2013-10-07:
- Adjust the stutter play position when setting a new cue
  point on the fly by pressing Shift + Cue while playing.
Merge pull request #78 from uklotzde/1.11_Vestax-VCI-300

Vestax VCI-300 Update for 1.11 (2013-10-04)
Vestax VCI-300: Adjust and fine-tune parameters

- Exactly measured the and adjusted jog resolution
  parameters. It's only 1600 instead of 1664 steps per
  revolution!! This was wrong since the initial version :(
- Synchronized jog feedback between scratching and cueing
  by using a linear response
- Slightly increased sensitivity for jog scrolling
- Some code cleanup
Merge pull request #113 from uklotzde/1.11_Vestax-VCI-300

Vestax VCI-300: Adjust and fine-tune parameters
Merge remote-tracking branch 'upstream/1.11' into 1.11-zwr