Echo conflicts with hide=True

[bitprophet]

E.g. run('something', hide=True) generally means "don't show the terminal that this is running at all, really", but inv -e <task with that run call in it> will still echo the command something in bold to the terminal. (Same if one directly does run('something', echo=True, hide=True).)

Should tweak it so that hide=True implies echo=False. I could see some use cases being mildly irritated by this, but I think it's far more likely that the current behavior is considered unintuitive.