DNSimple get_domain also accepts domain name

As the real DNSimple behaviour, get_domain also accept a string argument.
Added Openstack compute support for add_security_group and remove_security_group
[google] Expose Google API client, compute and api_url for easier debugging
Update rubygems to fix travis in ruby 1.8
Fix typos that make ruby 1.8 break
Merge pull request #2568 from josacar/master

[dnsimple] make get_domain also match to domain name
Merge pull request #2573 from maestrodev/google-debug

[google] Expose Google API client, compute and api_url for easier debugging
Merge pull request #2574 from maestrodev/travis-fix

Update rubygems to fix travis in ruby 1.8
Update Nokogiri version
Fixed method names for Mock objects for add/remove_security_group
Merge pull request #2571 from TranscendComputing/master

Added OpenStack support for add/remove_security_group functionality
Check if security group is nil, fixes #2507
Merge pull request #2569 from gaurish/security_group_check

Check if security group is nil, fixes #2507
Fix version
Undo last nokogiri version setting
Merge pull request #2575 from skorth/master

Update Nokogiri version