closes #672 add unwrap option and pass it to Gyoku

[TiteiKo]

So, this is a PR to fix this issue : #672

It depends on the merge of this PR on Gyoku : savonrb/gyoku#52, based on @stgwilli's work.

It adds an option :unwrap to Savon::Client to be passed to Gyoku, to be able to have this

a = { items: [ { item: { name: 'foo' } }, { item: { name: 'bar' } ] }

render this

<items><item><name>foo</name></item><item><name>bar</name></item></items>

instead of this

<items><item><name>foo</name></item></items><items><item><name>bar</name></item></items>

without breaking the actual behaviour.

[tjarratt]

Whoops -- I had forgot this was necessary to pass through, since Savon doesn't normally expose its options. I'm more than happy to merge this feature.

[tjarratt]

Released Savon v2.10.1 just now, which includes this change. Thanks so much!

[joenas]

Please add this to documenation, cause I had lots of trouble finding this option! Unless I'm very bad at looking and its already there?