remove need to provide nTaxa argument for tree distributions
merge fix for ctmc epoch
StandardState now uses max(size_t) for the ambiguous state instead of 0. Corrected StandardState to allow stateIndex computations when the number of states > 4 (solves dynamically instead of w/ lookup table. Since stateIndex is typically only called at preprocessing, should be safe.
add treatAmbiguousAsGaps flag
Merge branch 'development' of github.com:revbayes/revbayes into development
fixed PhyloCTMCEpoch to work with merged likelihood machinery