Initial parsing for SATISFIES ALL and SATISFIES ANY

### Story ###
- https://www.pivotaltracker.com/story/show/70537666

### Testing Strategy ###
- generate or acquire MAT (staging) SimpleXML export with <code>SATISFIES ALL</code> or <code>SATISFIES ANY</code> logic
- clone this repo and/or checkout this branch
- run ```bundle exec rake smiplexml:parse['/path/to/your/simplexml/file']```
- view <code>tmp/parsed/<your simplexml cms id>.json</code> and compare to targeted JSON structures below
- point latest Bonnie instance to this branch and upload the SimpleXML file and verify logic structure and patient builder behavior

### Notes ###
- includes <code>initialPopulation</code> when parsing SimpleXML
- handles <code>SATISFIES ALL</code> and <code>SATISFIES ANY</code> to target the following JSON structures:
```
Satisfies ALL
{
    "title" : "satisfiesAllExample",
    "description" : "Satisfies All Test",
    "children_criteria" : [ 
        "OccurrenceACataractSurgery1_precondition_113", 
        "OccurrenceACataractSurgery1_precondition_115"
    ],
    "derivation_operator" : "INTERSECT",
    "type" : "derived",
    "definition" : "satisfies_all",
    "hard_status" : false,
    "negation" : false,
    "source_data_criteria" : "satisfiesAllExample",
    "variable" : false,
    "comments" : []
}

Satisfies ANY
{
    "title" : "satisfiesAnyExample",
    "description" : "Satisfies Any Test",
    "children_criteria" : [ 
        "OccurrenceACataractSurgery1_precondition_113", 
        "OccurrenceACataractSurgery1_precondition_115"
    ],
    "derivation_operator" : "UNION",
    "type" : "derived",
    "definition" : "satisfies_any",
    "hard_status" : false,
    "negation" : false,
    "source_data_criteria" : "satisfiesAnyExample",
    "variable" : false,
    "comments" : []
}
```
Perhaps a quick comment on why the first two children are removed?