Minor improvements:
* Include canonicalised suite name in signed tag message.
* Mention cross-version dgit rpush incompatibility in manpage.
+ * Check for rpush protocol version incompatibility and crash early
+ if incompatible.
* New script tests/using-intree for running tests on the source tree.
* Do not spew diff output to terminal (by default). Print sensible
message instead. Closes:#736526.