Actually use size parameter.
Fixed comments in Registry.
Also set number of replicas to 0 during indexing so it's even faster.

Also wrap index setting in a try/finally block to make sure we set it back even if we raise an exception in between.
Raise a new exception if the get_indexes function can't find a valid index with the given name.
Pass in the index to recreate since we already know which.
Removed comment that was basically not useful and just a copy pasta.
Added some simple tests for the index management command.