Add check for point priors and force user to fix this parameter.

Traps Inf-prior

matlab/set_prior.m

@@ -155,6 +155,12 @@ end
 bayestopt_.p6 = NaN(size(bayestopt_.p1)) ;
 bayestopt_.p7 = bayestopt_.p6 ;
 
+%% check for point priors and disallow them as they do not work with MCMC
+if any(bayestopt_.p2 ==0)
+    error(sprintf(['Error in prior for %s: you cannot use a point prior in estimation. Either increase the prior standard deviation',...
+        ' or fix the parameter completely.'], bayestopt_.name{bayestopt_.p2 ==0}))
+end
+
 % generalized location parameters by default for beta distribution
 k = find(bayestopt_.pshape == 1);
 k1 = find(isnan(bayestopt_.p3(k)));