fix(Angular.js): handle duplicate params in parseKeyValue/toKeyValue

parseKeyValue and toKeyValue can now handle duplicate values in the query.
```
?x=1&x=2 <-> {x:[1,2]}
```

The algorithm looks like:
    1)parseKeyValue looks for presence of obj[key]
    2)detects and replaces obj[key] with [obj[key],val]
    3)then pushes more duplicates if necessary
    4)toKeyValue decodes array correctly
    5)(not changed)$location.search({param: 'key'}) still replaces if necessary
    6)(not changed)$location.search({param: ['key1', 'key2']}) sets the url with duplicates

BREAKING CHANGE: Before this change:
- `parseKeyValue` only took the last key overwriting all the previous keys;
- `toKeyValue` joined the keys together in a comma delimited string.
This was deemed buggy behavior. If your server relied on this behavior
then either the server should be fixed or a simple serialization of
the array should be done on the client before passing it to $location.

src/Angular.js

@@ -850,7 +850,14 @@ function parseKeyValue(/**string*/keyValue) {
       key_value = keyValue.split('=');
       key = tryDecodeURIComponent(key_value[0]);
       if ( isDefined(key) ) {
-        obj[key] = isDefined(key_value[1]) ? tryDecodeURIComponent(key_value[1]) : true;
+        var val = isDefined(key_value[1]) ? tryDecodeURIComponent(key_value[1]) : true;
+        if (!obj[key]) {
+          obj[key] = val;
+        } else if(isArray(obj[key])) {
+          obj[key].push(val);
+        } else {
+          obj[key] = [obj[key],val];
+        }
       }
     }
   });
@@ -860,7 +867,13 @@ function parseKeyValue(/**string*/keyValue) {
 function toKeyValue(obj) {
   var parts = [];
   forEach(obj, function(value, key) {
+    if (isArray(value)) {
+      forEach(value, function(arrayValue) {
+        parts.push(encodeUriQuery(key, true) + (arrayValue === true ? '' : '=' + encodeUriQuery(arrayValue, true)));
+      });
+    } else {
     parts.push(encodeUriQuery(key, true) + (value === true ? '' : '=' + encodeUriQuery(value, true)));
+    }
   });
   return parts.length ? parts.join('&') : '';
 }