Javascript array utility function to create an array of unique items
tests var o={first:1}; var aa=[4,4] a=[1,1,o,1,2,{second:2},1,3,3,o,4,aa,2,o,5,aa,4,o,6];
IS( JSON.stringify( Array.unique(a) ) ,"[1,{"first":1},2,{"second":2},3,4,[4,4],5,6]" ,'unique with mixed stuff - likely ECMA 6 mode');
IS( JSON.stringify( Array._unique(a) ) ,"[1,{"first":1},2,{"second":2},3,4,[4,4],5,6]" ,'unique with mixed stuff - ECMA 5 mode');
IS( JSON.stringify( Array.unique(a,function(x){return x;}) ) ,"[1,{"first":1},2,{"second":2},3,4,[4,4],5,6]" ,'unique with mixed stuff - likely ECMA 6 mode');
IS( JSON.stringify( Array._unique(a,function(x){return x;}) ) ,"[1,{"first":1},2,{"second":2},3,4,[4,4],5,6]" ,'unique with mixed stuff - ECMA 5 mode with function key finder');
var a2= [['one',1],['two',1],['three',1]];
IS( JSON.stringify( Array._unique(a2,function(x){return x[1];}) ) ,"[["one",1]]" ,'unique with mixed stuff - ECMA 5 mode with function key finder doing something');
IS( JSON.stringify( Array.unique(a2,function(x){return x[1];}) ) ,"[["one",1]]" ,'unique with mixed stuff - likely ECMA 6 mode with function key finder doing something');