Adds javadoc tasks for gradle.

Bolts/build.gradle

@@ -19,3 +19,13 @@ android {
         }
     }
 }
+
+android.libraryVariants.all { variant ->
+    task("generateBolts${variant.name.capitalize()}Javadoc", type: Javadoc) {
+        description "Generates Javadoc for $variant.name."
+        source = variant.javaCompile.source
+        ext.androidJar = "${android.plugin.sdkDirectory}/platforms/${android.compileSdkVersion}/android.jar"
+        classpath = files(variant.javaCompile.classpath.files) + files(ext.androidJar)
+        exclude '**/com/bolts/**'
+    }
+}

Bolts/src/bolts/AppLinkNavigation.java

@@ -361,9 +361,9 @@ public static Task<NavigationResult> navigateInBackground(Context context,
    * Navigates to an {@link bolts.AppLink} for the given destination using the App Link resolution
    * strategy specified.
    *
-   * @param context     the Context from which the navigation should be performed.
-   * @param destination the destination URL for the App Link.
-   * @param resolver    the resolver to use for fetching App Link metadata.
+   * @param context        the Context from which the navigation should be performed.
+   * @param destinationUrl the destination URL for the App Link.
+   * @param resolver       the resolver to use for fetching App Link metadata.
    * @return the {@link bolts.AppLinkNavigation.NavigationResult} performed by navigating.
    */
   public static Task<NavigationResult> navigateInBackground(Context context,
@@ -406,8 +406,8 @@ public static Task<NavigationResult> navigateInBackground(Context context,
    * Navigates to an {@link bolts.AppLink} for the given destination using the default
    * App Link resolution strategy.
    *
-   * @param context     the Context from which the navigation should be performed.
-   * @param destination the destination URL for the App Link.
+   * @param context        the Context from which the navigation should be performed.
+   * @param destinationUrl the destination URL for the App Link.
    * @return the {@link bolts.AppLinkNavigation.NavigationResult} performed by navigating.
    */
   public static Task<NavigationResult> navigateInBackground(Context context,