v2.1.0

Version 2.1.0 comes with a couple of new features:

• Logging - as verbose as you want it, to wherever you want it (not just stderr!)
• Logging now consolidates all of glib, libvips and govips into one channel
• imageRef.Close() is deprecated, it happens automatically nowadays

In addition, we've got:

• More, better examples and documentation
• Better unit test coverage