Removed assert: true when installing dpl gem
Make JVM builds aware of gradle wrapper

JVM alreads know about build.gradle to make builds using pre-installed
gradle binaries. But Gradleware recomends a feature[1] where a gradle
wrapper script can be used so build can be more smart about required
gradle versions.

This commit makes Travis smart about Gradle smartness.

[1]: http://www.gradle.org/docs/current/userguide/gradle_wrapper.html
Without sbt configuration, scala behaves like jvm

Avoid code repetitions between scala builder and other JVM languages, by
applying same rules for build tool detection (Gradle, Maven and Ant)
Maintain the same code style for checking file existence
Merge pull request #130 from gildegoma/dry-scala-and-jvm

Without sbt configuration, scala builder should behave like other jvm languages
Merge pull request #126 from andrewhr/ar-gradle-wrapper-for-jvm

Make JVM builds aware of gradle wrapper
Change DNS resolv entries to the Ashburn servers.
One less \
Hide output for change of DNS servers.
Remove examples.

He who needs examples shall run a command.
Add examples directory to .gitignore.
Create examples directory for tests.
Merge branch 'master' into no_deploy_assert

Conflicts:
	lib/travis/build/script/addons/deploy.rb
	spec/script/addons/deploy_spec.rb
Added allow_failure option
Removed allow_failure from config
Merge pull request #140 from travis-ci/mm-remove-examples

Remove examples
Made allow_failure an accessor
Merge pull request #125 from Aaron1011/no_deploy_assert

Conditionally allow deployment commands to fail

This'll help us implement travis-ci/travis-ci#1412 in a configurable way.
Merge branch 'master' into multiple_providers

Conflicts:
	lib/travis/build/script/addons/deploy.rb
	spec/script/addons/deploy_spec.rb