Add better support for JSON. Also json (yaml, csv) in default value.

[guyboertje]

Use Logstash::Json.

Re-organise the dictionary loading by file extension to save a reference to the loader method, so it can be reused to load the default value or fall back to plain string loading.

Use deep_clone to fix bug because a pointer to the dictionary was stored in the event - any mutation of the value would also mutate the value in the dictionary.

[guyboertje]

Jenkins please test this

[guyboertje]

The test fail on travis and jenkins for different reasons and both suck.

Travis is using logstash-core 2.3.0.snapshot1-java Jenkins is using logstash-core 2.1.1

[guyboertje]

Jenkins please test this

[guyboertje]

please jenkins, test this

[guyboertje]

please jenkins test this