fix to actually copy records in out_copy
add symlink to the latest buffer file
add format raw
Suppress dumping of whole configuratinos by default
Added `--dump-config-as-info` option to allow users to dump config at the log level INFO.
rename raw to none
Avoid calling Engine.flush! in trap context

Since Ruby 2.0.0, We can't synchronize mutex in trap context.

Currently USR1 handler calls `Fluent::Engine.flush!` in trap handler
(main thread) and it attempts to lock mutexes.

This separates thread to call `Fluent::Engine.flush!` to avoid that
limitation.

(Trap handlers run in main thread)

So this enables flushing via USR1 signal in Ruby 2.0.0 or later.
Merge pull request #182 from sonots/raw_parser

PROPOSE: add format raw
add deep_copy option and tests
Merge pull request #191 from sorah/avoid_flush_in_trap_context

Avoid calling Engine.flush! in trap context
Add rubinius test to allow_failures
More cleaner and robust implementation of DSLs for configuration

This PR removes ugly `__`-prefixed methods from config element object.
Merge pull request #196 from kentaro/config-dsl-refactoring

More cleaner and robust implementation of DSLs for configuration
simplify return
buffer: synchronizes @queue.delete_if
Make source_path of DSL a path, not a filename
Changed config dump strategy

  * default: dump config as it does till now
  * option: `--suppress-config-dump` as optional command line flag
Merge pull request #197 from tomykaira/run_dsl_with_path

Make source_path of DSL a path, not a filename
Merge pull request #179 from sabottenda/duplicate_record_in_OutputChain

Add 'deep_copy' option to out_copy plugin
in_tail: configure shouldn't cause side effects including creating file