jQuery URL docs is misleading and not aligned with that is actually done

[sevdog]

Currently what is stated in the docs is not aligned with what the code does:

django-smart-selects/docs/settings.md

Lines 3 to 10 in 1f3ac7c

	`JQUERY_URL`
	: jQuery 2.2.0 is loaded from Google's CDN if this is set to `True`. If you would prefer to
	use a different version put the full URL here. Set `JQUERY_URL = False`
	to disable loading jQuery altogether.
	`USE_DJANGO_JQUERY`
	: By default, `smart_selects` loads jQuery from Google's CDN. However, it can use jQuery from Django's
	admin area. Set `USE_DJANGO_JQUERY = True` to enable this behaviour.

django-smart-selects/smart_selects/widgets.py

Lines 16 to 51 in 1f3ac7c

	USE_DJANGO_JQUERY = getattr(settings, "USE_DJANGO_JQUERY", False)
	JQUERY_URL = getattr(
	settings,
	"JQUERY_URL",
	"https://ajax.googleapis.com/ajax/libs/jquery/2.2.0/jquery.min.js",
	)
	URL_PREFIX = getattr(settings, "SMART_SELECTS_URL_PREFIX", "")
	class JqueryMediaMixin:
	@property
	def media(self):
	"""Media defined as a dynamic property instead of an inner class."""
	media = super(JqueryMediaMixin, self).media
	js = []
	if JQUERY_URL:
	js.append(JQUERY_URL)
	elif JQUERY_URL is not False:
	vendor = "vendor/jquery/"
	extra = "" if settings.DEBUG else ".min"
	jquery_paths = [
	"{}jquery{}.js".format(vendor, extra),
	"jquery.init.js",
	]
	if USE_DJANGO_JQUERY:
	jquery_paths = ["admin/js/{}".format(path) for path in jquery_paths]
	js.extend(jquery_paths)
	media += Media(js=js)
	return media

Also there are no tests which ensures this beaviour.

The issues are:

• If JQUERY_URL=True it results in having a True as JS source, which ends up in an errore on frontend
• It is not documented that to use USE_DJANGO_JQUERY the JQUERY_URL should be a falsy value different from False (ie: empty string, 0, None, etc...)
• It is wrongly documented that using JQUERY_URL=True will make this package use the Google CDN, while this works if the settings is not defined

Some tests over this feature are required and also the docs should be more accurate.