Lowercase input of istartswith/iendswith (#1359)

To be symmetric with other case insensitive methods
that lowercase both operands in comparison

Author: glensc

Diff for: plexapi/base.py

@@ -22,9 +22,9 @@
     'lt': lambda v, q: v < q,
     'lte': lambda v, q: v <= q,
     'startswith': lambda v, q: v.startswith(q),
-    'istartswith': lambda v, q: v.lower().startswith(q),
+    'istartswith': lambda v, q: v.lower().startswith(q.lower()),
     'endswith': lambda v, q: v.endswith(q),
-    'iendswith': lambda v, q: v.lower().endswith(q),
+    'iendswith': lambda v, q: v.lower().endswith(q.lower()),
     'exists': lambda v, q: v is not None if q else v is None,
     'regex': lambda v, q: bool(re.search(q, v)),
     'iregex': lambda v, q: bool(re.search(q, v, flags=re.IGNORECASE)),