Update README.md

* Use Markdown syntax in more places
* Use syntax highlighting more
Minor JavaScript tweaks.

* fix undefined variable
* use the same quotes type
* enable strict mode
Minor CSS consistency changes.
Update index.html.

* losslessly compress the logo; saved 2.91 KB
* minor cosmetic changes
Merge pull request #3 from XhmikosR/js

Minor JavaScript tweaks.
Merge pull request #2 from XhmikosR/patch-1

Update README.md
Merge pull request #5 from XhmikosR/html

Update index.html.
Merge pull request #4 from XhmikosR/css

Minor CSS consistency changes.