GPGME::Crypto options are not documented

[do11]

http://www.rubydoc.info/gems/gpgme/GPGME/Crypto says

Different, independent methods providing the simplest possible API to execute crypto operations via GPG. All methods accept as options the same common options as GPGME::Ctx.new. Read the documentation for that class to know how to customize things further (like output stuff in ASCII armored format, for example).

Ok, I read http://www.rubydoc.info/gems/gpgme/GPGME/Ctx but there is no description or even list of at least :output, :recipients, :always_trust, :sign, :signer and who knows how much more.

It would be awesomely useful if documentation state full list of options. For example, I hoped there is option to specify encrypted file name (related to #62).