Remove registration methods from template tag

The registry isn't just for template tags anymore.

imagekit/specs/__init__.py

@@ -265,3 +265,16 @@ class SpecHost(object):
 
 
 registry = SpecRegistry()
+
+
+def register(id, spec=None):
+    if not spec:
+        def decorator(cls):
+            registry.register(id, cls)
+            return cls
+        return decorator
+    registry.register(id, spec)
+
+
+def unregister(id, spec):
+    registry.unregister(id, spec)

imagekit/templatetags/imagekit_tags.py

@@ -69,20 +69,3 @@ def spec(parser, token):
 
 
 spec = spec_tag = register.tag(spec)
-
-
-def _register_spec(id, spec=None):
-    if not spec:
-        def decorator(cls):
-            spec_registry.register(id, cls)
-            return cls
-        return decorator
-    spec_registry.register(id, spec)
-
-
-def _unregister_spec(id, spec):
-    spec_registry.unregister(id, spec)
-
-
-spec_tag.register = _register_spec
-spec_tag.unregister = _unregister_spec