improve attach
Merge branch 'master' into split_stdout_stderr_run-feature
split stdout and stderr in run if not -t
Add IP forwarding config to archlinux guide

I had this small issue when following this guide on my Arch box, and I don't think it is specific to any configuration I have.
if address already in use in unit tests, try a different port
always display help in the same order
Merge pull request #750 from dotcloud/ensure_order_help-fix

Always display help in the same order
* Documentation: removed 'building blocks' for now.
Merge pull request #747 from riccieri/patch-1

+ * Documentation: add IP forwarding config to archlinux guide
Merge pull request #741 from dotcloud/split_stdout_stderr_run-feature

* API: Split stdout stderr in docker run if no -t
Merge pull request #749 from dotcloud/unit_tests_use_available_port-fix

- Test: if `address already in use` in unit tests, try a different port