Change pipeline behaviour to execute all commands at the end of the block

[eoghanmurray]

(the behaviour I expected)

• see comment from @Fogapod Add an actual simple example! #155 (comment)

[Fogapod]

How about mentioning this in documentation and fixing examples?
Having a test for this would also be nice.

Also in redis-py only reset is called, creating slightly different behavior.

[eoghanmurray]

Thanks @Fogapod I've made the minimal set of changes to the docs and added a test case.

I've raised a similar issue in redis-py to see if there are any objections there:
redis/redis-py#1383