Making better use of `get_model()` to replace hardcoded `Comment` instances.

This makes comment form integration easier. Documentation updated.

@@ -9,7 +9,8 @@ from django.utils.encoding import force_text
 from django.utils.text import get_text_list
 from django.utils import timezone
 from django.utils.translation import pgettext_lazy, ungettext, ugettext, ugettext_lazy as _
-from django_comments.models import Comment
+
+from . import get_model
 
 COMMENT_MAX_LENGTH = getattr(settings, 'COMMENT_MAX_LENGTH', 3000)
 DEFAULT_COMMENTS_TIMEOUT = getattr(settings, 'COMMENTS_TIMEOUT', (2 * 60 * 60))  # 2h
@@ -127,7 +128,7 @@ class CommentDetailsForm(CommentSecurityForm):
         comment apps should override this, get_comment_create_data, and perhaps
         check_for_duplicate_comment to provide custom comment models.
         """
-        return Comment
+        return get_model()
 
     def get_comment_create_data(self):
         """

@@ -86,10 +86,6 @@ field::
     class CommentFormWithTitle(CommentForm):
         title = forms.CharField(max_length=300)
 
-        def get_comment_model(self):
-            # Use our custom comment model instead of the default one.
-            return CommentWithTitle
-
         def get_comment_create_data(self):
             # Use the data of the superclass, and add in the title field
             data = super(CommentFormWithTitle, self).get_comment_create_data()