Add --gemfile option to manage fluentd gems
Tests on Travis CI against rbx instead rbx-19mode

There is no support for rbx-19mode on Travis CI:
http://docs.travis-ci.com/user/languages/ruby/#Rubinius
Merge pull request #262 from kiela/master

Tests on Travis CI against rbx instead rbx-19mode
Merge pull request #261 from fluent/add-gemfile-option

Add --gemfile option to manage fluentd gems
ada add undef_method to fluent-debug
Merge pull request #264 from tatsu-yam/fluent-debug-mod

add undef_method to fluent-debug
merge "ruby" keyword for access of ::Kernel, issue #195
Relax Cool.io gem version
Guarantee the inclusion order for `include`

Since the Dir#glob returns results in a different order given different
operating system, We need to call Array#sort to guarantee the inclusion
order.
Fix outedated link of Fluentd document site
Merge pull request #266 from cynipe/guarantee-inlusion-order

Guarantee the inclusion order for `include`
Add <include path /> directive to include the configuration in elements
Add assert which checks  is not included in child elements
Add allow_include case
Merge pull request #267 from fluent/add-new-include-directive

Add new include directive
v0.10.44
Add args from 2nd to fluent.** internal messages
Merge in_tail_multiline into in_tail. refs #269
Merge pull request #270 from sonots/add_args_fluent_warn

Add args from 2nd to fluent.** internal messages
Fix buffer sharing problem and change callback signature