deprecate aliases in preparation for version 2

* deprecate `respond_to` in favour of `on`
* deprecate `add_block_listener` in favour of `on`
* rename `with` to `subscribe` in TemporaryListeners
* rename `add` with `subscribe` in GlobalListeners
* Move parsing of options from arguments in GlobalListeners
remove rbx from CI until rubysl-openssl is fixed
Merge pull request #81 from krisleech/deprecate-aliases

Deprecate add_listener, add_block_listener and respond_to