1.1.0: Packages Only

Adds the --packages-only flag which can be used to render a graph that omits libraries and targets.

What's Changed

• Adds --packages-only flag by @simonbs in #3
• Updates sample image by @simonbs in #5
• Fixes deadlock by @simonbs in #4
• Fixes clusters in union graph not containing all nodes by @simonbs in #6
• Bumps version number to 1.1.0 by @simonbs in #7

Full Changelog: 1.0.0...1.1.0