Force "main" sourceSet to "src/example/java" in CI

build.gradle

+subprojects {
+  apply plugin: "java"
+
+  sourceSets {
+    main {
+      java.srcDirs = ['src/example/java']
+    }
+  }
+}

prime-factors/build.gradle

   testCompile "junit:junit:4.12"
 }
 
-// ignore; used by track maintainers.
-sourceSets { example { } }
-dependencies { testCompile sourceSets.example.output }

robot-name/build.gradle

   mavenCentral()
 }
 
-
 dependencies {
   testCompile "junit:junit:4.10"
 }
 
-// ignore; used by track maintainers.
-sourceSets { example { } }
-dependencies { testCompile sourceSets.example.output }