DAISIE_sim_update_state: Updates state of island given sampled event
In joshwlambert/DAISIEsim:

Makes the event happen by updating island species matrix and species IDs. What event happens is determined by the sampling in the algorithm.

1 2	DAISIE_sim_update_state(timeval, totaltime, possible_event, maxspecID, mainland_spec, island_spec, stt_table)

`timeval`	current time of simulation
`totaltime`	simulated amount of time
`possible_event`	numeric indicating what event will happen.
`maxspecID`	current species IDs
`mainland_spec`	number of mainland species
`island_spec`	A matrix with species on island (state of system at each time point)
`stt_table`	A species-through-time table