Bugfix/timeout and sleep

[LukeJones123]

• Add timeout to session.get in Client.status which otherwise hangs on connection error
• Also add timeouts in Result.update and Result.delete which presumably would also hang
• Reorganise Client.robust to avoid an unecessary final sleep after the final try and have it raise an Exception rather than return None, which creates problems elsewhere

[FussyDuck]

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