Remove illegal use of @api

This is very selfish of me - it's just to reduce the number of warnings we get from Closure Compiler... I hope you don't mind :-)

@api is not actually part of JSDoc - http://usejsdoc.org/

We currently get this warning

```
JSC_BAD_JSDOC_ANNOTATION: Parse error. illegal use of unknown JSDoc tag "api"; ignoring it at line 52 character 5
   * @api public
```