Write logger output to stderr to conform to convention

Writing log to stdout causes issues when piping.
Update Nokogiri version
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
Merge pull request #2390 from revapost/master

Write logger output to stderr to conform to convention
rm rspec dependency
Switch to DNSimple versioned API
Cleanup documentation and resource representations

Remove deprecated attributes and make the documentation more consistent.
Add support for Rackspace's Extract Archive API call
See http://docs.rackspace.com/files/api/v1/cf-devguide/content/Extract_Archive-d1e2338.html
for documentation on the API call
Set the Content-Type of extract_archive requests to ''
The documentation for extract archive (http://docs.rackspace.com/files/api/v1/cf-devguide/content/Extract_Archive-d1e2338.html) says if a Content-Type is sent, every object in the archive will have its Content-Type set to that value. However, if a blank Content-Type is sent, CloudFiles will determine it based on each individual file. Since we don't want every file to be interpreted as an archive (which would happen if we let Fog determine the Content-Type), we set it explicitly to a blank string.
Remove :host key in SQS request method to eliminate excon error
Use @ in comment for YARD docs
Merge pull request #2585 from smeyfroi/sns_fix_for_excon_parser_change

Remove :host key in SNS request method to eliminate excon error
Merge pull request #2581 from weppos/dnsimple-versioned

[dnsimple] Add support for versioned API
Merge pull request #2579 from josephholsten/rm-rspec

rm rspec dependency
Fix typo puplic -> public
Merge pull request #2583 from codeodor/master

Add support for Rackspace's Extract Archive API call