Release 10.3.

Optional service method parameters, deferred void service functions and
a couple of bugfixes. For more information, consult debian/changelog.
Bump Python dependencies.

Upload size fix for cocaine-tool depends on patches in Python Framework
0.10.2-1.
Support for optional types in io::type_traits.

Optional types couldn't be packed with io::type_traits, because the
system had no idea what to do with them and how to measure the sequence
length if it had optional elements in it.
Proper distribution name in the changelog.

Wise people say that the distribution name in the Debian changelog
should not include Ubuntu distribution names explicitly. Well, okay.
Merge branch 'master' into ipvs.

Pull in 0.10.3 release stuff into the active development.
Proper log message wording for locator.

Some more verbosity for the locator log messages never hurts.