Merge pull request #197 from researchgate/alter_plugin

[FEATURE] Alter filter plugin
- add future note and set plugin_status to experimental (#197)
Note new filter: alter (#197)
unset collect_file_and_line (#205)

Conflicts:

	lib/logstash/outputs/gelf.rb
Update contributors
Added a TAI64N date format.

This is a format commonly used by daemontools multilog. It does
something a but funny with the first byte to do with pre 1970 dates,
which my parsing ignores.
Added support for milliseconds

Parsed the nanosecond part to obtain millisecond accuracy. Also
removed redundant casting to integer
Update changelog/contributors
Cleaned up debugging output.
remove debug print
- blah, Hash#merge doesn't modify the hash itself, need to use #merge!
Merge branch 'master' of https://github.com/logstash/logstash
First commit of the geoip plugin
More debugging. Added teardown support.
Fix spelling error in CLI help
Merge pull request #210 from drnic/patch-1

Fix spelling error in CLI help
Add drnic
Switch from using poll method to receive_message to reduce duplicate messages and improve speed.
Fixed comments. Updated documentation. Replaced erroneous 'puts' with logger calls.
Added '?' to URIPARAM

Added the '?' character to URIPARAM to handle an edge case