Consider adding a "Highlight" functionality

[jwildfire]

Add controls (toggles?) that will highlight/gray out points based on decision rules using key variables. Common Default Decision rules could be added (or users could make rules themselves). Possible defaults are:

1. ALT/TB in a given quadrant a given threshold
2. AST/TB in a given quadrant
3. ALP > a given value
4. Move R Ratio here also?

Goal is to make it easier to identify Hy's Law candidates in the population view, instead of having to drill down to participant details repeatedly.

(Based on feedback from Jack @ Rho)