Hopefully, can add collection operations

[vampireslove]

json data:
{
"strs": [
{
"s1": "a",
"s2": "b"
},
{
"s1": "a",
"s2": "c"
},
{
"s1": "c",
"s2": "b"
}
]
}
1.contains mathc an object
json data Can match {"s1":"a","s2":"b"}

2. contains mathc multiple objects
   json data Can match [{"s1":"a","s2":"b"},{"s1":"a","s2":"c"}]

3.memberOf
strs of json data is memberOf [{"s1":"a","s2":"b"},{"s1":"a","s2":"c"},{"s1":"c","s2":"b"},{"s1":"c","s2":"d"}]
4.memberOf

strs of json data equal [{"s1":"a","s2":"b"},{"s1":"a","s2":"c"},{"s1":"c","s2":"b"},{"s1":"c","s2":"d"}]

[thiagolvlsantos]

Issue #2 implementation changed to allow subsets on "attribute" name.

Next move, write some tests to check if this new impl already accept these cases.