Bug 1061684 - Normalize path separators in JAR paths; r=mshal

The forward slash appears to be the standard path separator in zip/JAR
files. Accept back slashes when adding paths to a JAR.

--HG--
extra : rebase_source : bd94eab36b347006e65952d99b53dd397e2ca758
extra : amend_source : 2cefd887d8bb5d989fafb398a3464429ac376e2e