Rename has_key-vs-lookup.rb in gemspec.

This file was renamed in 30e455d.
Merge pull request #220 from dprince/fix_gemspec_has_key

Rename has_key-vs-lookup.rb in gemspec.
fix warnings around class level variable access
include scheme in socket key

closes #223
make socket#connect a private method

see also #222
add Excon.stub_for

allows lookup of stub and/or nil
closes #209
Release 0.21.0
remove request/response info from HTTPStatusError message

This prevents Excon from inadvertently displaying sensitive information,
and producing large error messages when request[:body] is a String.

All HTTPStatusError exceptions provide access to the request and
response, and may be rescued and inspected for debugging purposes.

Closes #219
Merge pull request #219 from burns/issue-219

Redact request body in HTTPStatusError message
handle problems with default ports and redirects
Include example using `URI.encode_www_form`
Informational comment including target Content-Type
Add proper header `x-www-form-urlencoded` for this type of request
Line breaks for readability
Merge pull request #226 from brandur/encode-www-form

Include example using `URI.encode_www_form`
small fix for consistency related to streaming mock responses
move streaming out of mock middleware

now any middleware can set datum[:response] and get streaming
closes #207
consistency/performance tweaks for default ports
add option for omitting the port (no longer default)
Merge remote-tracking branch 'chrisrhoden/feature/default_port_dropping'