implement #options.

[technoweenie]

This implements Faraday::Connection#options almost as expected, fixing #305.

We can't rename the current :options attr_reader right now for backwards compatibility reasons. Instead, this overloads the method to support both use cases. Merging the two risks some clashing, but I can only think of one issue: the other request helpers like #get can be called with no arguments:

conn = Faraday.new 'http://example.com'
conn.get # GET /
conn.options # oops!

You can get around this easily with conn.options(nil). I think it's worth introducing this regardless of the risk, assuming we'll rip it out when v1.0 ships.

[olleolleolle]

This addition - with documentation - extends the reach if the user, to include a new HTTP verb.

👍

[iMacTia]

Ignoring CodeClimate issues, not sure they actually make sense in this case