Jenkins support - don't select stdin when interactive=False

Resolves #4 

(includes the branch in #23, which will need to get merged first anyway)

Requires one change to fig as well:

```diff
diff --git a/fig/cli/main.py b/fig/cli/main.py
index 2cb7d02..2c35980 100644
--- a/fig/cli/main.py
+++ b/fig/cli/main.py
@@ -7,7 +7,7 @@ import signal
 from operator import attrgetter
 
 from inspect import getdoc
-from fig.packages import dockerpty
+import dockerpty
 
 from .. import __version__
 from ..project import NoSuchService, ConfigurationError
@@ -337,7 +337,7 @@ class TopLevelCommand(Command):
             print(container.name)
         else:
             service.start_container(container, ports=None, one_off=True)
-            dockerpty.start(project.client, container.id)
+            dockerpty.start(project.client, container.id, interactive=not options['-T'])
             exit_code = container.wait()
             if options['--rm']:
                 log.info("Removing %s..." % container.name)
```