• add support for the multivariate normal distributions in small dimensions by Miwa's method thanks to Tetsuhisa Miwa and Xuefei Mi; both have been added as `authors'.
• new argument `algorithm' defaulting to `GenzBretz()' with `Miwa()' being the alternative. Those two functions are now used to specify hyper parameters such as `abseps'.
• internal function `mvt' is no longer exported.