Remove extra ';' outside of function macros

This may be a bit pedantic, but because `LAYER_ACCESSOR`, `LAYER_MUTATOR` and `LAYER_RW_PROPERTY` are simply generating setter/getter methods, there is no need to terminate their use with a semicolon.

![Screenshot](https://f.cloud.github.com/assets/647626/2418129/956c9f32-ab37-11e3-8462-69d29f8056de.png)