util.json: utils for converting arbitrary types to json
Rewrite value_to_json using built-in Liftweb decompose mechanism
Remove xmldesc and __repr__ debug code
add implicit ordering for SphereCoord
Add (untested) convex-hull code for SphereCoord
AnalyzeLocationVariance: Rewrite to output human-readable info
AnalyzeLocationVariance: Add histogram generation