- Add Math class with container textbox creation
- Implement mc:AlternateContent wrapper for compatibility
- Add automatic formatting with <a:rPr> elements
- Create MathShape wrapper class
- Add add_math_equation() method to SlideShapes
- Fix CT_T text property in math.py
- Update user documentation with working examples
- Support slide-level OMML storage as required by PowerPoint

This enables proper rendering of mathematical equations in PowerPoint
through the correct container structure and compatibility wrappers.

Resolves: PowerPoint equation rendering with proper OMML integration