Use __signature__ (but probably incorrectly)
Merge branch 'master' into python3
Merge branch 'master' into python3
Catch inspect.signature import error

With this modification, the main functionality should be portable to
python2. The __signature__ will only be retrieved and used if the
platform has support for this feature.
Add python3 specific tests for preserving the signature

Sorry for the extra top level folder. It seems nosetests has no real
support for excluding individual tests based on runtime version.

There are the --py3where and --where options that could be used. Though,
with one of these enabled the entire test is run from the specified
subdirectory. Which means that all top level content has to be symlinked
in order to provide a valid runtime without the module installed.
Merge branch 'python3-signature'