Can't run ./bin/scala-petstore.sh as instructed at README

The instructions do not work, because the default is to use Scala 2.9.1 but BeanProperty moved - see #208 and # 233 

Switch the default to use 2.10.3, which does work, add a 2.11 target (which works too), and fix the client test, which was broken because Tag is ambiguous. I left the 2.9.1 profile in, but arguably it could be removed.

This fix does mean it works out the box, which is helpful :)

The test code is not being autogenerated, right? I couldn't find any template. 

Fixes #208 and #233