Maintain quotes for boolean values in defaultSnippets

[JPinkney]

In a default snippet if the body has a quoted boolean value we want to maintain the quotes for that boolean value:

 {
     "label": "foo",
      "description": "Foo",
      "body": {
           "bar": "true"
      }
}

So when inserted it becomes bar: "true".

Likewise, if the boolean value is not quoted then we don't want to keep quotes.

So when inserted it would become bar: true

See: #225 (comment)

[coveralls]

Coverage increased (+0.1%) to 77.247% when pulling 85a3131 on defaultSnippets-boolean-fix into be89eea on master.