fix race condition which causes redis output to lose some messages in batch mode

Scenario:
  - @flush_thread starts writing to redis (@redis.rpush)
  - main thread adds a new message to @pending
  - @flush_thread deletes this message (@pending.delete)
add myself to contributors list
use Stud::Buffer for batch mode

pending the acceptance of https://github.com/jordansissel/ruby-stud/pull/2
and a new release of stud.
add merge verb
Create a filter that should clone events.

The next step is to figure out which type of test needs to be written and
then write it.
Fix a copy and paste error in the clone filter.

It was still using a variable name from the split filter.
Merge remote-tracking branch 'upstream/master'
Update patterns/grok-patterns

Fix the hour pattern to accept single digit hours, fixes an issue with timestamps like that: "2013-02-21 6:23:46"
Renamed mcollective patterns in the traditional app style
Removed mcollective base pattern since it's just the standard Ruby pattern
Merge pull request #371 from alexkoltun/patch-1

Make 'HOUR' accept single-digit hours.
Merge pull request #363 from AldenJole/feature/clone-filter

Feature/clone filter
Merge pull request #362 from gza/master

New function for mutate filter
Merge pull request #354 from alexdean/redis_output_with_stud_buffer

Redis output with generalized batch/flush