feat: refactor forms/grids/views/templates per wuttaweb compat

this starts to get things more aligned between wuttaweb and tailbone.
the use case in mind so far is for a wuttaweb view to be included in a
tailbone app.

form and grid classes now have some new methods to match wuttaweb, so
templates call the shared method names where possible.

templates can no longer assume they have tailbone-native master view,
form, grid etc. so must inspect context more closely in some cases.

tests/views/test_users.py

@@ -0,0 +1,33 @@
+# -*- coding: utf-8; -*-
+
+from unittest.mock import patch, MagicMock
+
+from tailbone.views import users as mod
+from tailbone.views.principal import PermissionsRenderer
+from tests.util import WebTestCase
+
+
+class TestUserView(WebTestCase):
+
+    def make_view(self):
+        return mod.UserView(self.request)
+
+    def test_includeme(self):
+        self.pyramid_config.include('tailbone.views.users')
+
+    def test_configure_form(self):
+        self.pyramid_config.include('tailbone.views.users')
+        model = self.app.model
+        barney = model.User(username='barney')
+        self.session.add(barney)
+        self.session.commit()
+        view = self.make_view()
+
+        # must use mock configure when making form
+        def configure(form): pass
+        form = view.make_form(instance=barney, configure=configure)
+
+        with patch.object(view, 'viewing', new=True):
+            self.assertNotIn('permissions', form.renderers)
+            view.configure_form(form)
+            self.assertIsInstance(form.renderers['permissions'], PermissionsRenderer)