Code review comment for lp:~leonardr/lazr.restful/bump-version

This branch adds multi-version tests for the WADL generation. When I tried to give multi-version features to lazr.restfulclient, it didn't work because the WADL was malformed. The two main problems were:

1. Unless you got the WADL for the latest version, lazr.restful saw multiple registrations for an entry adapter and crashed. This is because lazr.restful was looking for registrations that matched the marker interface (let's say) IWebServiceVersion1_0. But IWebServiceVersion2_0 and IWebServiceVersion3_0 subclass IWebServiceVersion1_0, so the entry adpater registrations for those versions were picked up as well.

2. The stub function that signals the removal of a named operation as of a particular version was being treated as a (malformed) named operation in its own right.

I fixed these problems in ways that should make sense when you look at the code.

This branch also fixes a test failure and prepares a new release of lazr.restful. (I thought that would be the only purpose of this branch, until lazr.restfulclient started failing on me.)