“… first, it must be shown that the evidence could not have been obtained with reasonable diligence for use at the trial; secondly, the evidence must be such that, if given, it would probably have an important influence on the result of the case, though it need not be decisive; thirdly, the evidence must be such as is presumably to be believed, or in other words, it must be apparently credible, though it need not be incontrovertible.”