Has been mitigated a lot by v0.5.0. The error is to the order of 1.43e-14 now.
Watch Bug #1662 about Fisher's exact test
Out of scope
Monitor bug #16332 regarding pbeta
Fixed in v0.5.0
Watch resolution of R's bug #8528 regarding pgamma
Watch bug #15554 about Bessel functions
Integrate methods not public