minor clarification in comment on doeachint
Gamma detection function problems

 * Standardisation was being applied to detection functions (such that
g(0)=1) when there were no adjustments (which is uneccesary) but also
caused issues when using gamma detection functions as this should be
calculated at g(apex) instead. Standardisation code has been removed for
when there are no adjustments and the correct scaling used for the gamma
when there are. Thanks to Thomas Doniol-Valcroze for alerting us to this
bug.
 * Tests for gamma detection functions