Formatted code to be uniform and centered menu
--index.html--
replaced 4 spaces with tab for more uniform code

--stylesheet.css--
replaced 4 spaces with tab for more uniform code
removed margin-left: auto; in .menu selector - does not do anything
added text-align: center; to .menu seletor to center top menu
Merge pull request #2 from jackd1/master

Formatted code to be uniform and centered menu