This place, and a few others below it, I think we need to be more careful with.  `OutOfMemoryError` is a sub class of `VirtualMachineError`, so it's already taken care of here (ie, immediately rethrown).  The problem is that the definition of `NonFatal` is pretty arbitrary - it's what the Akka team decided is not fatal, which is different to what we think is not fatal, and all depends on context.  For example, `NotImplementedError` is not fatal in our opinion, nor is `NoClassDefFoundError`, since these errors are common in dev mode, and we want to handle them and render the error to the user in their browser.  But `NonFatal` considers these fatal.  So I think these and the instances below should be reverted.