Add dummy log device and fix to use it
 * remove setting global logger in lib/fluent/test.rb
   * developer cannot understand when this assignment happen
   * global logger assignment exists in test/helper
 * dummy logger should contain messages that logger writes
   * to assert logger's output from core/plugin tests
 * test dummy logger is set in default in create_driver
   * to test logger message in configure
Merge pull request #308 from tagomoris/test_dummy_logger

Add dummy log device and fix to use it
Update travis.yml
Merge pull request #311 from sonots/travis_2.1

Update travis.yml
add option to show logs with source host/addr/port and its tag when large chunk arrived
Fix log typo, and tests
 * We cannot determine when data chunk is processed over send_data
   * On high load host, background I/O handler doesn't wake up long time.
   * "sleep" approach is not deterministic
 * Call Plugin#on_message directly to execute event processing on current thread
fix variable name for consistency
fix single statement rescue and value assignment syntax
fix the misnamed tail watcher in in_tail.
Move supervisor default options to supervisor.rb
Merge pull request #315 from uu59/move_default_option_for_fluentd

Move supervisor default options to supervisor.rb
Allow empty value parameter in v1 config
Merge pull request #310 from tagomoris/in_forward_size_threshold

show logs with source host/addr/port and its tag when large chunk arrived
Make parameter name and log message more clear. ref #310
Merge pull request #316 from fluent/allow-empty-value-parameter

Allow empty value parameter in v1 config