Merge lp://staging/~bloodearnest/django-preflight/optional-settings into lp://staging/django-preflight

LGTM

Branch looks good, but can we please make the default be False?

Expanding a bit on my former comment: having settings enabled by default makes much easier to expose sensitive data through the preflight overview page, because the gather_settings function is not smart about hidding settings inside a dict.

So, if we will leave the "show settings" defaulting to True, I would please request that preflight will copy/reuse the logic in django/views/debug.py:26:

def cleanse_setting(key, value):
    """Cleanse an individual setting key/value of sensitive content.

    If the value is a dictionary, recursively cleanse the keys in
    that dictionary.
    """
    try:
        if HIDDEN_SETTINGS.search(key):
            cleansed = '********************'
        else:
            if isinstance(value, dict):
                cleansed = dict((k, cleanse_setting(k, v)) for k,v in value.items())
            else:
                cleansed = value
    except TypeError:
        # If the key isn't regex-able, just return as-is.
        cleansed = value
    return cleansed

09:35 < nessita> bloodearnest, branch looks great, I'm approving. Any chance you can add a test where a setting inside a dict is expected to be masked?
09:35 < nessita> such as the database setting
09:39 < bloodearnest> nessita, good idea, will do
09:39 < nessita> bloodearnest, thanks, will leave my vote in there