Add Ruby 2.1.0 to the test matrix
Merge pull request #2511 from petergoldstein/feature/add_ruby_2_1_0_to_travis

Add Ruby 2.1.0 to the test matrix
ignore more Ruby version manager files

Both rbenv and rvm now generate some files that have no bearing on
the project, and leave the local repo in a dirty state.
drop dependency on deprecated ruby-hmac gem, fixes #2034

Ruby 1.8 compiled against OpenSSL 0.9.8 supports SHA256 for some time now.
Ref: https://github.com/ruby/ruby/blob/ruby_1_8_7/ChangeLog#L12025-L12029
Merge pull request #2512 from miketheman/ignore_ruby_managers

ignore more Ruby version manager files
[AWS|EC2] request_spot_instances.rb requires that date parameters be iso8601
[AWS|EC2] fix sporadically failing network_acl_tests.rb
[digitalocean|compute] add created_at timestamp as attribute of server

* We receive this field from Digital Ocean, so all we need to do to use it is add it as an attribute and it just works
[digitalocean|compute] additional test coverage and some maintenance

* Add created_at field to mock response
* Assert that the created_at field is returned
* Update references to nonexistent images
[storm_on_demand] don't pass host to request
delete snapshots and address requests for google
[aws] mock block device mapping on run_instances
Fix subnet mocking, related to #2510
Fix DhcpOption#associate
Merge pull request #2518 from drcapulet/master

Fix subnet mocking, related to #2510
Merge pull request #2514 from fcheung/request_spot_instances_time_coercion

[AWS|EC2] request_spot_instances.rb requires that date parameters be iso...
Merge pull request #2520 from engineyard/aws_block_device_mapping

[aws] mock block device mapping on run_instances
addresses and settags
[aws] mock setup block device deleteOnTermination
Merge pull request #2522 from engineyard/aws_block_device_mapping

[aws] mock setup block device deleteOnTermination