2.1.0

• ActiveJob support [tarzan#71]
• adding be expired in matcher [bernabas#72]
• Fixed testing failures with be_delayed matcher due to rename of enqueued_at to created_at in latest Sidekiq [philostler]
• Add support for NullBatch#on and NullStatus#failures to the null batch objects. [PacerPRO#64]
• Adding a save_backtrace matcher [webdestroya#61]
• Add flag to skip Batch stubs [paulfri#69]
• allow passing an instance method to be_delayed matcher [lastobelus#63]