Renable javadoc fail on error (#631)

Remove reference check and fix HTML error

wpilibj/publish.gradle

@@ -51,9 +51,9 @@ task sourcesJar(type: Jar, dependsOn: classes) {
 task javadoc(type: Javadoc, overwrite: true) {
     javadoc.options.links("http://docs.oracle.com/javase/8/docs/api/")
     options.addStringOption "tag", "pre:a:Pre-Condition"
+    options.addStringOption('Xdoclint:accessibility,syntax,html', '-quiet')
     source = sourceSets.main.allJava
-    options.addStringOption('Xdoclint:accessibility,syntax,reference,html', '-quiet')
-    failOnError = false
+    failOnError = true
 }
 
 task javadocJar(type: Jar, dependsOn: javadoc) {

wpilibj/src/main/java/edu/wpi/first/wpilibj/vision/package-info.java

@@ -9,7 +9,7 @@
  * Classes in the {@code edu.wpi.first.wpilibj.vision} package are designed to
  * simplify using OpenCV vision processing code from a robot program.
  *
- * <p>An example usecase for grabbing a yellow tote from 2015 in autonomous:
+ * An example usecase for grabbing a yellow tote from 2015 in autonomous:
  * <br>
  * <pre><code>
  * public class Robot extends IterativeRobot
@@ -84,6 +84,5 @@
  *
  * }
  * </code></pre>
- * </p>
  */
 package edu.wpi.first.wpilibj.vision;