instances() now greps output with (optional) search string
instances() now greps output with (optional) search string

There's more value in being able to grep across all output
fields. We were previously reducing the data returned from
aws by filtering remotely on tag:Name but there generally
aren't so many instances that this makes much of a
performance impact.

jonhiggs/bash-my-aws,okstyr/bash-my-aws,cbweixin/bash-my-aws,realestate-com-au/bash-my-aws,limed/bash-my-aws,bossjones/bash-my-aws,azrupani/bash-my-aws,gdhbashton/bash-my-aws