[xtend examples] fixed manifest and tests. Removed TypeReference#operator_equals and TypeReference#is.

TypeReference#is was removed as we decided to support properly implemented equals and hashcode. Inferred type references won't lazily resolve (i.e. mutate). During the first two phases those type references are always inferred. During validation and generation we create proper TypeReference instances again.

Change-Id: I3eaf01a8702a09b77aed88b899d67f0650600ed4
[441779] Warn when a deprecated feature is used.