gtFitSpotPosDeviations: added comment

Signed-off-by: preischig <preischig@gmail.com>

zUtil_Fit/gtFitSpotPosDeviations.m

@@ -6,6 +6,10 @@ function duvw = gtFitSpotPosDeviations(newvars, activeglobal, spot, gr, par)
 %   duvw  - deviations in u,v,w in one vector (3*no_of_grains,1):
 %           [all_du; all_dv, all_dw]
 %
+% If no strain of the grains is fitted, it uses gr.plref to compute spot
+% positions. So it may account for existing strain, depending on how
+% gr.plref was computed.
+%
 %
 % Version 001 18-04-2014 by P.Reischig
 %