Connection memoization

[laserlemon]

Connections are being memoized incorrectly when they're created in Twitter::Connection#connection because the given options are being ignored. Currently, only options[:endpoint] affects the resulting Faraday connection so this change memoizes created connections once per given endpoint.

This issue would pop up if one were to make a rate limit request (one endpoint) and then use the same client to make a search request (different endpoint). The search request would be performed on the first (memoized) endpoint.

[sferik]

Looks good. Other than endpoints is there anything we need to worry about being cached?

[laserlemon]

The endpoint is the only option we actually use in the connection method so no, nothing else at the moment. Unless a client's own configuration changes after initialization for some reason.