Merge pull request #2 from grossjo/rage4_dns_support

Rage4 dns support
Merge remote-tracking branch 'upstream/master'
Merge branch 'master' of github.com:grossjo/fog
Merge remote-tracking branch 'upstream/master'
Release 1.21.0
Adding support for udplimit paramater in rage4 api
making tests ruby 1.8.7 friendly
Merge pull request #2775 from grossjo/rage4_udp_limit_support

Rage4 udp limit support
[core] Remove providers/ directory from core fog gem
Remove deprecated `host` Excon option from dynamodb
Merge pull request #2780 from pedro/remove-deprecated-host-option-from-dynamodb

Remove deprecated `host` Excon option from dynamodb
Merge pull request #2779 from domcleal/gemspec-no-providers

[core] Remove providers/ directory from core fog gem