ruby filter: multi-instance support
Merge pull request #501 from nikicat/fix-ruby-filter

ruby filter: multi-instance support
- try to fix prune specs, but I think there are actually bugs found by
  the tests that need fixing now.
- fix range filter specs
- fix split filter specs
- fix translate filter specs
- default useragent filter to target the root of the event instead of
  writing into the "ua" field.
- fix useragent specs
- fix xml specs
Fix another json spec failure (typo)
- fix alter filter specs
- fix failling clone filter spec (Event#clone wasn't a deep enough copy)
- fix multiline specs
- added 'source' setting to multiline filter now that there's no
required "@message" field (due to event v1 schema)
Disable the 'prune' filter spec because the test should have always failed, but it didn't, and I'm not sure what to do next...
Style improvements; alsos kip the event if it doesn't have the given source field
event v1
A recent change to the test_utils.rb made filter yields appear earlier than the 'return' event, so updating the clone test to acknowledge the order change
- no more sys/uname
Fix some support-originating specs
basic codec framework with eventv1 schema