robnb function

Calculates the estimate and standard error of beta and phi. It takes as input counts from one group of samples for a single gene. This function is the core underlining function of the whole package. A significant part of the code is edited based on William H. Aeberhard's glmrob.nb R function; we appreciate them very much for sharing their code online. This function also implement Algorithm 1 of our submitted paper about DiPhiSeq. This function is called by robtest. Most users don't need to call this function directly.