remove obsolete _get_named_object
python plugin
move python deployer to airship.contrib.python
rename python configuration options
move python plugin test to its own module
add test for virtualenv activation
bucket.run sends bucket_run signal
plugins receive `airship` instance as argument
signal receives airship object as sender argument
bucket_run signal called with airship as sender
move virtualenv activation code to python plugin
extract `create_command` function
hook for adding subcommands
load entry points at module level
'sarge wheel' command to build wheels
Merge branch 'python-plugin'