update_tree_ob_speciate: Update Simulation Object with Speciation Event
In rdinnager/nichefillr: Niche Filling Simulations in R

Function to update simulation object by adding add_br_len to the tips, then splitting a tip into two species

1	update_tree_ob_speciate(tree_ob, split_tip, mult = 1)

`tree_ob`	The simulation object to update
`split_tip`	Integer expressing which tip number to split into two sister species
`mult`	Multiplier which determines the proportional increase in trait evolution rate at a speciation event. This causes species to diverge more rapidly than usual if greater than one. Generally used to make sure a speciation is accompanied by a 'jump' in trait values, which helps them not immediately go extinct from competition