Support for oauth with RSA-SHA1 signing
Bumped oauth-sign version to 0.4.1
Merge branch 'feature/oauth_sign_rsa' of github.com:toehio/request into toehio-feature/oauth_sign_rsa

Conflicts:
	request.js
Upgrade oauth-sign to v0.5.0
For RSA OAuth we want to specify private_key instead of consumer_secret.
Update OAuth documentation for RSA-SHA1 signing
Add tests for RSA-SHA1 OAuth signing

Also abort all OAuth requests to make this test file complete more
quickly.
Merge pull request #1228 from nylen/toehio-feature/oauth_sign_rsa

Support for oauth with RSA-SHA1 signing
Document how to use custom CA in README (#1229)