a few minor changes to help with understanding dimensionality sliders

  - trigger add:link
  - link checker looks for coeffs, not strength
  - link checker uses dataProvider.filter, not minStrength
  - linkHistogram is always 0 to 1
Merge branch 'master' into uap-dimension-slider
reset link checker
remove default link checker
Merge pull request #67 from jdhenke/uap-dimension-slider

changes necessary for jdhenke's uap dimension slider