Make MockRedis#pipelined yield itself

As Redis#piplined does:
https://github.com/redis/redis-rb/blob/v3.0.4/lib/redis.rb#L2030

Change-Id: Ia1b4c665d4549407ff4e1b1bd413b1d6529af66c
Reviewed-on: https://gerrit.causes.com/24220
Tested-by: Lann Martin <lann@causes.com>
Reviewed-by: Shane da Silva <shane@causes.com>
Cut 0.8.1 release

Change-Id: I02dfdd0c7f519b08fd56ce09f4e4fa46ed94dd0e
Reviewed-on: https://gerrit.causes.com/24277
Tested-by: jenkins <jenkins@causes.com>
Reviewed-by: Lann Martin <lann@causes.com>
Integrate Travis CI

Change-Id: I469991ee85439f1839a3b4ffd7c430a41d00d8d6
Reviewed-on: https://gerrit.causes.com/24326
Tested-by: jenkins <jenkins@causes.com>
Reviewed-by: Shane da Silva <shane@causes.com>
Allow specs to run in Ruby 2.0