Added Channel#set_options and Channel#options= aliases

[ghost]

Resolves #271

Channel#set_options (RSL7) was implemented as Channel#update_options.
Added aliases: Channel#options= and Channel#set_options

[owenpearson]

LGTM, thanks

[owenpearson]

Actually, I'm not 100% sure on this. @lukaszsliwa What's the reason for the second alias? And can we emit a deprecation warning for people using update_options so that we can give people a chance to migrate to set_options and then we can remove update_options in the next major release.

[ghost]

Actually, I'm not 100% sure on this. @lukaszsliwa What's the reason for the second alias? And can we emit a deprecation warning for people using update_options so that we can give people a chance to migrate to set_options and then we can remove update_options in the next major release.

I added second alias because it is more natural for ruby but spec says that it should be set_options.

[TheSmartnik]

While set_options isn't very rubyish it adheres to the doc and options= is an idiomatic ruby method. We do add aliases purely for convenience so I guess it's a good idea