Fix google closure compiler JSC_TRAILING_COMMA errors

When running ua-parser.js though gcc I get these errors.

Paste:
```
// ==ClosureCompiler==
// @compilation_level SIMPLE_OPTIMIZATIONS
// @output_file_name default.js
// @code_url https://raw.github.com/faisalman/ua-parser-js/master/ua-parser.js
// ==/ClosureCompiler==
```

into: http://closure-compiler.appspot.com/home to see the errors.