Merge pull request redis#371 from go-redis/fix/try-go14-fix

Try to fix Go 1.4.

Merge pull request redis#368 from go-redis/fix/cmdable-iface

Fix Cmdable interface.

Merge pull request redis#366 from go-redis/fix/option-defaults

Set some sane default for every day usage.

internal/pool: improve tests.

Merge pull request redis#361 from vkd/v4

fix iterator across empty pages

Merge pull request redis#356 from domodwyer/v4

Add Cmd constructors for testing/mock purposes.

Merge pull request redis#355 from go-redis/fix/geo-pos-rename

Fix/geo pos rename

Merge pull request redis#352 from jrmarkle/process_wrapper

add WrapProcess to allow users to alter command processing

Merge pull request redis#350 from go-redis/fix/ring-heartbeat-frequency

ring: reduce HeartbeatFrequency.

Merge pull request redis#347 from flisky/master

fix iterator for hscan/sscan/zscan