Code improvements and styling rework

[acikek]

• Styling logic is now more dynamic than before. A UIStyling object is a ruleset that determines an element's UIStyle each frame. This paradigm is much more capable at a reasonably low cost. There are many avenues for future optimization.
• Constructors are now more brief, and working with elements is more flexible as a result. There is still work to be done on this front, but these changes are sufficient for the work I need to do.

Note on UIStyle field renames

I have found terminology like fill, stroke, and weight to be idiomatic across the industry. I like these words because a UIStyle is a palette (of colors, and more) to use when drawing an element.