Add IPv6 grok pattern.

Rename IP pattern to IPV4 and add new IP pattern that matches either IPV6 or
IPV4 patterns.

IPV6 regex swiped from http://forums.intermapper.com/viewtopic.php?t=452
outputs/riemann: make event tagging work again

As tags on outputs are now deprecated, we pass the tags set at input or
filter stage to Riemann events.

For the record, the idea is to pass along Logstash's events tags to the
Riemann events created, so that filtering *in Riemann* can be done based
on the tags set by Logstash.
outputs/riemann: minor cleanups

 - remove trailing whitespace
 - clarify how tags work + other small documentation updates
Add option to specify canned ACL in AWS S3 output configuration

    * Adds the option "canned_acl" which defaults to "private"
    * Breaks the previous behaviour where the canned ACL was hard-coded to "public_read".
      Which is a potential security problem, allowing everyone to access the file on S3.
Unbreak twitter input by using the twitter gem.
Put tweet text into the message field.
[rabbitmq] Disable automatic connection recovery for input, fixes LGOSTASH-1350

See LOGSTASH-1350.

Automatic recovery was added after the plugin was rewritten.
In logstash's case, full control over how recovery
is performed is probably more important than
removing some plugin code.
[rabbitmq] Disable automatic connection recovery for output

Related to LGOSTASH-1350.
proof-reading grok doc + comments
Merge pull request #651 from wiibaa/grok-docs

Small enhancement by proof-reading grok doc + comments
fix broken graphite codec spec
Merge pull request #642 from michaelklishin/patch-2

[rabbitmq] Disable automatic connection recovery for output
Merge pull request #641 from michaelklishin/patch-1

[rabbitmq] Disable automatic connection recovery for input, fixes LGOSTASH-1350
Merge pull request #640 from bernd/fix-twitter-input

Unbreak twitter input by using the twitter gem
Discovered sha128 was not a valid digest in the openssl lib
Add tests for the checksum filter.
Merge pull request #652 from logstash/filter-tests

More filter tests
Merge pull request #631 from mfournier/riemann-tags-issue

riemann plugin: make tagging work again
Merge pull request #637 from hduregger/cannedAcl

Add option to specify canned ACL in AWS S3 output configuration
Merge pull request #623 from bodgit/ipv6

Add IPv6 grok pattern.