Fix "Login-As"

When using the login-as with the login password auth, the login-as header was never added. This release fixes that.

"Login As" feature

• New logAs method in Authenticators
• You are now able to use the API with one of your sub-account should you possess one, without specifying its password.

0.10.1

• Fix a bug with autoloading of ApiKey class
• Fix a bug where headers were not correctly added to the request

0.10.0

• Use of new API endpoint for JSON-RPC requests : https://api.callr.com/json-rpc/v1.1/ See #16
• Deprecate CALLR\API\Client::setAuthCredentials and CALLR\API\Client::setAuthToken in favor of CALLR\API\Client::setAuth. See #15
  These will be removed in future versions, so please switch to the new method using a CALLR\Authentication\AuthenticationInterface object. Please see README for updated docs.
• Deprecate CALLR\API\Client::setURL. If you really need to change the endpoint, please extend the CALLR\API\Client class. See #16

v0.9.2

Merge pull request #14 from THECALLR/updates/api

- update documention to reflect new website address
- update code to futureproof api endpoint updates
- add user-agent headers to request

0.9.0

v0.9.0

feat(proxy): setProxy()