creates a copy of a orderbook, stripping all history (orders etc)
clone.orderbook(orderbook.st, cloned.orderbook.st, strip.history = TRUE,
src_envir = .strategy, target_envir = .strategy)
string identifying the source orderbook
string naming the target orderbook
boolean, default TRUE, whether to remove all orderbook history, keeping only the structure (e.g. assets)
environment to get the source orderbook from, default .strategy
environment to put the cloned orderbook in, passed to put.orderbook