Search custom criteria

Some times we need to do custom queries to mongo collections. 
Now We can send request.data.criteria with values that matchs config search for that collection.

with config:
```
Scheds: {
...
    criteria: { between: '{ "start": { "$gte": %value% }, "end": { "$lt" : %value% } }' },
...
}
```

And request.data
```
{ criteria: {between : [1375903885730 , 1375904497520]  } }
```

And the create mongo criteria matching this.