Simplifies SpecRunner.html

No need to specify type="text/javascript" for script tag
No need to specify type="text/css" for link tag with rel="stylesheet"

Less bytes and improved readability is always better :) IE8 also happy

Sources:
- [Why write script type=“text/javascript”](http://stackoverflow.com/questions/2706290)
- [meta charset='utf-8' vs meta http-equiv='Content-Type'](http://stackoverflow.com/questions/4696499)
- [Do we need type=“text/css” for link in HTML5](http://stackoverflow.com/questions/7715953)