Fix breaks due to Gradle 3 upgrade?

I am so glad you took the time to create this example. Unfortunately, after forking then cloning this project onto my Mac 10.13.1, opening the project within Android Studio 3.0.0, seeing ADB appear, I got this error message:

```
Error:Execution failed for task ':app:javaPreCompileDebug'.
> Annotation processors must be explicitly declared now. The following dependencies on the compile classpath are found to contain annotation processor. Please add them to the annotationProcessor configuration.
- butterknife-6.1.0.jar (com.jakewharton:butterknife:6.1.0)
Alternatively, set android.defaultConfig.javaCompileOptions.annotationProcessorOptions.includeCompileClasspath = true to continue with previous behavior. Note that this option is deprecated and will be removed in the future.
See https://developer.android.com/r/tools/annotation-processor-error-message.html for more details.
```
I Googled the messages and found:
https://developer.android.com/studio/build/gradle-plugin-3-0-0-migration.html?utm_source=android-studio#annotationProcessor_config

https://stackoverflow.com/questions/42993587/setting-explict-annotation-processor

So I editing the project-level build.gradle file to end up with
classpath 'com.android.tools.build:gradle:3.0.1'

Then I clicked Sync.

In gradle-wrapper.properties I have:
distributionUrl=https\://services.gradle.org/distributions/gradle-4.1-all.zip

Following [(https://developer.android.com/studio/build/gradle-plugin-3-0-0-migration.html#annotationProcessor_config] I added:

annotationProcessor 'com.jakewharton:butterknife-gradle-plugin:6.1.0'

But this resulted in errors as well.
So I'm lost here. Suggestions?

Start with the project-level build.gradle and gradle-wrapper.properties, then reproduce the Gradle sync in Android Studio 3.0.0 using the versions described in the report. Compare the annotation-processor configuration with the reported Butter Knife dependency and verify that the project syncs and builds without the javaPreCompileDebug error.

Written by the indexing model from the issue text.