Add BREAD_CRUMB_TRAIL.

This new option makes it possible to specifically disable the "Inherits from" text that appears in class definitions.

This option is off by default.

This is being used at nimbuskit.info. Example: http://v2.nimbuskit.info/NimbusKitCoreDataCodingConfigurationOptions.html.

![screen shot 2014-07-19 at 1 53 56 pm](https://cloud.githubusercontent.com/assets/45670/3634047/8056e3a8-0f11-11e4-9f13-c08269ed3db7.png)