Add basic docs, remove stub get_context_data

Author: jieter

django_tables2/columns/templatecolumn.py

@@ -15,6 +15,7 @@ class TemplateColumn(Column):
     Arguments:
         template_code (str): template code to render
         template_name (str): name of the template to render
+        context_object_name (str): name of the context variable to pas the record in, defaults to "record".
         extra_context (dict): optional extra template context
 
     A `~django.template.Template` object is created from the
@@ -25,6 +26,7 @@ class TemplateColumn(Column):
     - *default*     -- appropriate default value to use as fallback.
     - *row_counter* -- The number of the row this cell is being rendered in.
     - any context variables passed using the `extra_context` argument to `TemplateColumn`.
+      If ``extra_context`` is a callable, it will be called with optional record, table, value, bound_column arguments.
 
     Example:
 
@@ -91,6 +93,3 @@ def value(self, **kwargs):
         """
         html = super().value(**kwargs)
         return strip_tags(html).strip() if isinstance(html, str) else html
-
-    def get_context_data(self, **kwargs):
-        return