4363: Fix filename munging. Add tests.
4363: Reject NUL characters in filenames in CollectionWriter.
4363: Test that munged filenames show up in os.listdir().
4363: Test edge cases as directory names, too.
4363: Remove redundant test.
4363: Validate utf-8 encoding of manifest_text.
4363: Explicit UTF-8 for test string.
4363: Merge branch 'master' into 4363-less-filename-munging
4363: Specify ASCII encoding in test case.
4363: Accept manifest_text in a non-UTF-8 encoding that is equal to its UTF-8 encoding.
4363: Fix size hints for multi-byte manifests (backported from f78caf9).
4363: Fix flaky test case (race with filterable.js debounce timer).
Merge branch '4363-less-filename-munging' closes #4363