Minify the tree view

[svenevs]

The tree view unordered list or javascript version needs to be minified, large-ish projects and page loads are taking an unnecessary hit. Add a configuration argument "minifyTreeView" defaulting to True. Maybe this means that a TreeView config object should be introduced as well in v1.0.0.

exhale_args = {
    # no "treeView" key => None => RST lists
    "treeView": {
        "type": "str",# "collapse" or "bootstrap"
        "minify": True # optional entry
    }
}

Can be flexible in the parsing, e.g. also allow "treeView": "collapse|bootstrap"?