0.11.0

What's Changed

• Disambiguates alignment modifiers - aligning the contents of a sequence is now done with align_contents instead of align
• Improves the consistency of constraint handling at the root of a layout tree & in stacks.
• Adds the option to expand a sequence node to take up more space than it's contents require.
• Adds constraint caching to prevent redundant traversal.
• Fixes attach_over & attach_under

• Constraints by @ejjonny in #58

Full Changelog: 0.10.1...0.11.0