Breaking changes

In #107, we started using our fork of Swagger UI in LoopBack Explorer. While our fork added several enhancements to the original project, we were not able to keep the fork up to date with upstream. As a result, several important fixes and improvements made upstream were not available to Explorer users.

In 3.0.0, we have reverted back to using the original swagger-ui module.

See #182 for more details.