Removed assert: true when installing dpl gem
Added support for deploying to multiple providers
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
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
Fixed tests
Only set up the DNS change when it's using non-default DNS hosts.
improve allow_failure for deploys
Merge pull request #137 from Aaron1011/multiple_providers

Added support for deploying to multiple providers
Don't expect assertion when running 'dpl' tool
Merge pull request #144 from Aaron1011/fixed_spec

Don't expect assertion when running 'dpl' tool
Merge branch 'master' into rkh-casher
do not print casher commands