Prefer ./gradlew to gradle in README
Prefer ./gradlew to gradle in README

- Using ./gradlew locks the Gradle version. Newer versions of Gradle
  removed StyledTextOutputFactory, on which the dependency management plugin
  depends.

Pinwheeler/Parrit,Parrit/Parrit,Pinwheeler/Parrit,Parrit/Parrit,Pinwheeler/Parrit,Parrit/Parrit,Parrit/Parrit