[core/widget] Add widget class

To maintain backwards compatibility (and because I think it's an OK
design choice), keep the widget concept (a single module can produce
multiple widgets).

core/widget.py

@@ -0,0 +1,15 @@
+import util.store
+
+class Widget(util.store.Store):
+    def __init__(self, full_text):
+        self._full_text = full_text
+
+    def full_text(self, value=None):
+        if value:
+            self._full_text = value
+        else:
+            if callable(self._full_text):
+                return self._full_text(self)
+            return self._full_text
+
+# vim: tabstop=8 expandtab shiftwidth=4 softtabstop=4