Add JSON output property to convert enclosed attribute groups to inline properties.

(Imported from Google Code)
Currently, attribute groups are enclosed in a named property like this, to match the class structure of DDMSence:

{
"security": {
"excludeFromRollup": true,
"securityAttributes": {
"classification": "U",
"ownerProducer": [
"USA"
]
}
}
}

It would be useful to provide a configurable property that converts this to inline attributes, for easier traversal:

{
"security": {
"excludeFromRollup": true,
"classification": "U",
"ownerProducer": [
"USA"
]
}
}