Fixes Issue #13: Optimized plugin for faster animation and readability improvements

[rakesh-vajrapu]

Optimizations and Readability Improvements:

• Cached jQuery objects for better performance.
• Optimize countTo plugin for faster animation by reducing speed parameter to 500 milliseconds
• Used the Number function to ensure data attributes are treated as numbers.
• Validated input values for numeric attributes.
• Moved the formatter function into $.fn.countTo.defaults for modularity.
• Improved code readability by breaking down into smaller functions.
• Added comments for better understanding of the code.