Extract battleground data

[kevdougful]

It would be nice to be able to extract battleground data from the HotS directory as well.

Maybe something like:

{
    "id": 1,
    "name": "Infernal Shrines",
    "description": "Demonic corruption threatens the Gardens of Hope. Called forth by the Shrines, Punishers prowl the battlefield, terrifying creatures that live to destroy heroes.  Defeat the Shrines' Guardians before your enemies do, and the next Punisher will fight for you; fail, and face the demon's wrath.",
    "objectives": [
        {
            "name": "Activate the Shrines",
            "description": "The Infernal Shrines periodically gather power.  Activate them and prepare for a fight."
        },
        {
            "name": "Defeat Guardians",
            "description": "Slay 40 Guadians before the enemy team to bring forth a mighty Punisher."
        },
        {
            "name": "Beware the Punisher",
            "description": "Punishers have one of three devastating powers.  Be careful, they focus on attacking heroes above all else."
        }
    ]
}