Faster cloneAndReplace in newJO flags

The cloneAndReplace used to always deep copy all the flags. That is a bit slow and not needed when the flags are locked. Tagging @wlampl (and @sshaw who reported slowness of newJOs - this should help a bit) One other thing, I have moved tests to a separate file. In normal jobs we do not need them. @wlampl & @khoo - this MR also contains hashing function I mentioned (in case you wonder why such implementation of the hash: https://stackoverflow.com/questions/49722196/how-does-python-compute-the-hash-of-a-tuple).