templatetags: add template tag to render a blurp block in a template

Blurp blocks doing things with placholders or cms-plugin instances will
not work.

setup.py

@@ -85,6 +85,7 @@ setup(name="django-cmsplugin-blurp",
       packages=find_packages('src'),
       install_requires=[
           'django>1.5',
+          'django-classy-tags',
           'django-cms>3',
       ],
       package_dir={

src/cmsplugin_blurp/templatetags/blurp_tags.py

@@ -0,0 +1,26 @@
+from django import template
+
+from classytags.arguments import Argument
+from classytags.core import Options, Tag
+
+from .. import utils
+
+register = template.Library()
+
+class RenderBlurp(Tag):
+    name = 'render_blurp'
+    options = Options(
+        Argument('name', resolve=False),
+    )
+
+
+    def render_tag(self, context, name):
+        renderer = utils.resolve_renderer(name)
+        if not renderer:
+            return ''
+        template = renderer.render_template()
+        context = renderer.render(context, None, None)
+        if not hasattr(template, 'render'):
+            template = template.Template(template)
+        return template.render(context)
+register.tag(RenderBlurp)