Fixes #2432. Implements Dim.Auto for Content including subviews.

[tig]

DimAutoStyle.Text is now complete and merged in #3416.

Fixes

• Fixes Add Dim.Auto to automatically size views based on Text and/or Content #2432

Proposed Changes/Todos

• Fully implement/test DimAutoStyle.Content
• Implemement Dim.AutoSize (max: dim)
• Use Dialog and MessageBox as test cases - This will require moving the dialog buttons to Padding as adornments.
• Dive deep into all other PosDim objects and get clarity on behavior relative to Dim.Auto - Improve unit tests to validate
  • Dim.Absolute
  • Dim.Auto
  • Dim.Fill
  • Dim.Function
  • Dim.Width/Height
  • Pos.Absolute/At
  • Pos.AnchorEnd
  • Pos.Function
  • Pos.Anchor
  • Pos.Percent
  • Pos.Center
  • Pos.X/Y etc...

[tig]

Abandoning this PR. I'll create a new Issue and PR to finalize DimAutoStyle.Content after #3480 is merged. It makes a bunch of progress on this.