Document NRoot and Trig, some other clean up.
Document NRoot and Trig, some other clean up.

siddhartha-gadgil/spire,adampingel/spire,tixxit/spire,JackSullivan/spire,tixxit/spire,rklaehn/spire,woparry/spire,codeaudit/spire,non/spire,AlecZorab/spire,rklaehn/spire,JackSullivan/spire,kevinmeredith/spire,codeaudit/spire,woparry/spire,AlecZorab/spire,adampingel/spire,guersam/spire,non/spire,kevinmeredith/spire,siddhartha-gadgil/spire,guersam/spire