remove positive number validation for getRow ind.

If useID is True, then ind can be of value 0

+types/+util/+dynamictable/getRow.m

@@ -10,7 +10,7 @@
 
 validateattributes(DynamicTable,...
     {'types.core.DynamicTable', 'types.hdmf_common.DynamicTable'}, {'scalar'});
-validateattributes(ind, {'numeric'}, {'positive', 'vector'});
+validateattributes(ind, {'numeric'}, {'vector'});
 
 p = inputParser;
 addParameter(p, 'columns', DynamicTable.colnames, @(x)iscellstr(x));