classify_da_id: Classify da_pa_ids
In avrincon/phukieo: Manipulate Behavioural Data

Checks if an aggression inside a da_pa_id was given or received at least once. Prioritises high intensity over low.

1	classify_da_id(x, agg.low, agg.high, id, tag = NULL)

`x`	A data frame of focal observations
`agg.low`	A character vector of low intensity aggression codes
`agg.high`	A character vector of high intensity aggression codes
`id`	A character vector of aggression partner IDs
`tag`	A character string that denotes the class of aggression partner. will be added to the new column name. e.g. "mm" or "mf".