[util] Add 'formatting' utility methods

Add helpers to unify formatting of bool/list/int values.

util/format.py

@@ -0,0 +1,26 @@
+
+def asbool(val):
+    if val is None:
+        return False
+    if isinstance(val, bool):
+        return val
+    val = str(val).strip().lower()
+    return val in ('t', 'true', 'y', 'yes', 'on', '1')
+
+def asint(val, minimum=None, maximum=None):
+    if val is None:
+        val = 0
+    val = int(val)
+    val = min(val, maximum if maximum else val)
+    val = max(val, minimum if minimum else val)
+    return val
+
+
+def aslist(val):
+    if val is None:
+        return []
+    if isinstance(val, list):
+        return val
+    return str(val).replace(' ', '').split(',')
+
+# vim: tabstop=8 expandtab shiftwidth=4 softtabstop=4