Minor version bump (v1.20.0)

Features:

Add container rename

Bug fixes:

Docker::Error::ConfictError to Docker::Error::ConflictError
Docker::Image.build_from_dir is now threadsafe

Minor version bump v1.19.0

Updates Remote API to 1.16
Adds exit code to Docker::Exec#start!
Calls `close_write` on IO if necessary after STDIN attach ends

Minor version bump (v1.18.0)

Add support for calling a block for each line when pulling an image

Minor version bump v1.17.0

* Add support for saving Images
* Use the correct connection when refreshing an Image
* More robust implementation of pushing images

Patch version bump 1.16.1

This version has a more robust version of Docker::Image.create.

Minor version bump 1.16.0

This version adds exec functionality and supports the remote API up to
version 1.15

bump version to 1.15.0

Version bump v1.14.0

Version bump v1.13.7

Patch version bump 1.13.6